The art of travelling light is to make sure you have nothing superfluous to your trip, while at the same time ensuring that what you carry will enable you to do what you want and live wherever you choose. So careful thought about the countries and terrain you will be visiting, the mode of transport you are using and the type of activities you will be involved in will greatly help to reduce bulk. For example, if you are heading off on a trip to the Far East you will probably not need a tent as there are few places to camp, in fact accommodation is so cheap that the intrepid traveller will only need to take a mosquito net and hammock.

With the technical advances of recent years, as a rule of thumb you can safely assume that the more lightweight and compact the equipment is (all performance factors being equal), the more expensive it will be. For example, a good sleeping mat will cost approximately 20, while a modern self-inflating mat that combines both air and foam comes in at under a quarter of the size and is more comfortable, but will set you back around £60.

Adaptability and versatility are the key to travelling light. Use one item to fulfil many functions - for example, a poncho can be used as a rain garment to cover you and your pack, a ground sheet, a bivvi shelter or a sleeping bag cover.

When I first came to lightweight backpacking, I knew very little and did not bother to ask for advice. I learned from bitter experience and, interspersed with episodes of extreme misery, very exciting it was, too.

The main drawback to equipping oneself adequately is expense. Costs soon mounted to prohibitive proportions before I had what I wanted. The lesson? If you are beginning, a little advice is worth a lot. When you become more practised, that is the time for bitter experience to take over.

In this article, I intend only to cover the main purchases you will make, missing out food, clothing, and any technical sporting equipment. This leaves (in descending order of probable cost) tent or shelter, sleeping gear, rucksack, boots and cooking and eating gear.

If you are going backpacking, there are a number of objectives you should have in mind. Weight is usually at the top of the list: you want everything to be as light as possible. Performance: you want your equipment to be good enough for everything you are going to put it through. Expense: you have to be able to afford it. These three criteria form the eternal triangle of backpacking.

As we go on, you will see compromises arising, but one aspect of weight can be covered now. Most lightweight gear comes marked with a weight, but manufacturers being manufacturers, these are not always as accurate as they might be. Furthermore, some sleeping bags come marked with the weight of the filling only. It is easy to become confused or misled. The easiest answer is to shop for your kit armed with a spring balance (anything that measures up to eight kilos is sufficient, as long as it can be read to the nearest gram or two). If you want to know where to get a balance, ask a fisherman.

Tents and shelters

At one time, the ridge pole was the only tent you could get, short of buying a marquee. Then some bright spark designed an A-pole ridge so that the pole did not come straight down the doorway. Today both these designs are still around, and the ridge pole (in the form of the Vango Force Ten) is still preferred by many as a heavy-duty tent that can take a lot of punishment.

However, with the advent of flexible poles that could be shoved through sleeves, new designs became possible and these had their own advantages. Such models give you plenty of headroom, something as important as ground space if you intend to live in your tent during bad weather. There are disadvantages, of course. These tents are both more expensive and more fragile. To get a structurally strong flexible-pole tent, you have to go upmarket and seek out geodesic designs - and that costs a lot of money.

After the innovation that came with flexible poles, Gore-Tex was next to make its mark on the tent scene when it was used in the construction of single-skin tents. Water-tight with built-in breathability, the fabric gives you a condensation-free tent that weighs even less than regular flexible-pole types. These tents also tend to employ flexible poles, so the space inside is good. However, Gore-Tex is a very expensive material, so as the weight goes down, the prices go up.

Single-skin tents soon became available in one-man versions with only the barest skeleton of a frame. Because the material breathes, it does not matter if there is no circulation of air around it. With a hoop at the front, these tents resemble a tunnel that you have to crawl into feet first. Then the hoop was removed and the Gore- Tex 'bivi-bag' was born - a waterproof and fully breathable covering for your sleeping bag. These are probably the ultimate luxury in bivouacking, but the cost is again high. However, weighing in at next to nothing, these bags are well worth considering (although it is a bit like sleeping in a coffin).

Last, but not least, comes the humble bivouac sheet or, to use the army parlance, the 'basha sheet'. This two-by-three-metre piece of PU nylon has tags around the outside that allow it to be pegged down. It is the most versatile, lightweight, inexpensive and durable of all shelters so far discussed. It is limited only by the ingenuity and expertise of the user - and therein lies its fault: you need to know how to use it. But if you do not have any money, or if you can put the occasional soaking down to experience, give it a go. (The alternative for the backpacker travelling in warmer climates would be a waterproof poncho that can be used as a basha in combination with a mosquito net and hammock.)

So which tent do you choose? Narrow the field by asking yourself these questions: how many people do you want it to sleep? How high up are you going to camp? (The higher you camp, the harsher the conditions, so the sturdier the tent you need.) Is headroom important to you? (Perhaps you want a flexible hoop design.) Do you want it to last a long time? (If so you will have to go for a more sturdy, heavy-duty model.) It has to be said that even if you designed the tent yourself, compromises would have to be made, so be prepared to make them when buying. However, with care and proper scrutiny of the maker's specifications, you should get something suitable.

Whatever you end up with, try to get a tent with mosquito netting on every entrance, even the vents. Rare indeed are the countries with no flying biters. The tent you end up with will probably have a super-thin groundsheet to save weight, so you might want to get some 2mm foam to use as an underlay. It will keep you surprisingly warm and will cut down on wear and tear. However, this will add to the weight and bulk of your tent system. Bear this in mind before you reject the heavier tent with the stronger groundsheet.

Sleeping gear

The difficulty in choosing sleeping gear for the traveller is more extreme than it is for the expedition member as an expedition is usually based in one area, allowing you to equip yourself for that particular environment. The traveller, on the other hand, will more often than not encounter a variety of conditions. For example, a trip to India might include lazing on tropical beaches, travelling on crowded trains and hiking through the high and cold Himalayas. The solution comes with 'layering'. Go for the lowest common denominator for a sleeping bag, then make sure you have a good, thin base-layer top (many on the market now have high wicking properties and are stylish enough to wear as a T-shirt in warm weather), a down waistcoat or fleece jacket - when these are all combined you should have ample sleeping gear. If you end up travelling in more extreme conditions it is always possible to buy cheap local bedding to add on to your kit and dispose of it after the need has passed.

Another lightweight luxury to take with you is a pillowcase into which you can stuff fleece or cloth for added padding - or with which you can cover suspect pillows in cheap accommodation.

Without a shadow of a doubt, the best you can sleep in is a down bag. It promotes fine dreams, is aesthetically pleasing, is lighter for any given warmth rating than any other fill and packs away smaller than any other bag, lofting up afterwards to cosset you at night. Nothing else comes close to down unless, of course, you are allergic to feathers. Yet down has a terrible Achilles heel. If it gets wet, it is next to useless and becomes very unpleasant. Furthermore, wet it a few times and it starts to feel extremely sorry for itself, losing efficiency rapidly. It is also worth bearing in mind that a down bag can be difficult to clean while away and can become fetid on extended expeditions, so constant airing and the addition of a sleeping bag liner becomes vital.

If your bag is likely to get wet, steer clear of down. The alternative is a man-made fibre bag. These come in many guises, but the underlying principle is the same. A long, man-made fibre is hollow and thus traps air. As with down, it is the trapped air that keeps you warm. Call it Holofill, Superloft, Microsoft or whatever, the consensus of opinion is that the difference in performance is marginal. The fibres probably differ to get around patents rather than to improve performance.

The advantages of artificial fibres are clear. The bags are cheaper than down, they are warmer underneath you (because they are harder to compress), they keep you warmer when wet and they are easier to keep clean. Disadvantages? They are somewhat heavier and bulkier than down (although this is becoming less of an issue as these fabrics improve), and will not last you anywhere near as long.

The compromise is clear. If you can stay out of the wet and can afford to pay more, invest in down, which lasts longer and therefore costs the same in the long run. If you camp a lot in areas where you are likely to get wet, buy a man-made fibre bag and stick to stroking the down bags in the shops lovingly.

Another alternative is the Buffalo Bag, which is made from fibre pile covered in Pertex. These bags are unique and have their own special advantages, though the disadvantages can be stated easily: they are very heavy and bulky. Buffalo Bags are based on the layer system, making it handy to add layers for cold weather and subtract them for hot. They are tough and washable. Thanks to the Pertex covering, they do not get wet easily, and if they do so, the pile wicks away moisture and the Pertex cover dries it out rapidly. The same Pertex covering makes the bag very windproof. The bag is good for those who bivouac and can be used to effect with a good down inner bag. Handle, or better still, borrow one to try before you buy.

Another alternative for the 'lightweight tropical traveller' is the tropical quilt. This offers the best pack size and economy in tandem with a range of functions. It can be formed into a lightweight sleeping bag, wrapped around you on buses and trains and can be washed and dried in 20 minutes. It can also be doubled with a waterproof poncho to create a basic sleeping unit.

Try the bag on in the shop, however foolish you feel, and leave your clothes on while you do so. This minimises embarrassment, and one day you might be cold enough out in the wilds to sleep fully clothed. Pull the hood of the bag tight around your face to cover your head. If you cannot do this, the bag cannot be used in cold weather. A large part of the body's heat loss is from the head. Shove your feet into the bottom of the bag and wriggle. If the bag constricts you, it is too small. Any point where you press against the bag will turn into a miserable cold spot at night. If you are a restless sleeper, make sure the bag is wide enough around the middle to contain all your squirming. If you feel like a pea rattling in an empty pod, the bag is too large and you will waste heat warming up empty space.

General points to look for in a bag include a box- or elephant-type foot, a draw-cord at the shoulder as well as the headband the option of a right- or left-handed zip so that, in an emergency, you can share your warmth with an extra-special friend. Zips should all be well baffled to prevent loss of heat. If the sack you choose is of man-made fibre, check to see if it comes with a compression-stuff sack. If it does not and you want one, this will add a few pounds to the final price.

I have deliberately ignored baffle constructions as the subject is complicated and best covered with examples to hand. Seek advice on-site. Similarly with the season rating of the bag: a 'season' system is simple but should only be used as a rough guide. One season (summer) for very casual use in warm weather, two seasons (summer and spring) is a little better, three seasons should be good for winter use and five seasons for use in severe conditions. However, simple systems such as this leave room for manufacturers to fudge their claims. One man's three seasons is another man's four, it really depends on how much you feel the cold.

Query the general reputation of the bag you fancy with as many experts as you can find. I find that the 'lowest temperatures' quoted for the bags are next to useless: they are inevitably rated for still air, and who camps in that? As well as ignoring the massive effect of wind chill, they can also ignore the fact that some people maintain a higher body temperature at night than others.

Last but not least with sleeping gear, you would be well advised to put something under your sleeping bag; namely a 'kip mat'. The most widely used is the closed-cell foam type, which is bulky but lightweight and durable. Ignore all advice that tells you that they are all made of the same stuff and that, when it comes to the expensive ones, you simply pay for the name - it is patently untrue. A simple test is to inflict severe damage on various types - such damage as scoring, tearing, and compressing flat. Choose one that withstands these injuries best - it will probably be the one that feels warmest when pressed between the palms. It will probably cost more, but in my experience the cheap ones are simply not worth it. A modern alternative is the self-inflating mat. This is a quarter of the pack size of a traditional mat and uses a combination of air and foam. Its drawbacks are that it is three times more expensive than a conventional mat and that great care must be taken to avoid punctures. A puncture repair kit is, therefore, an essential extra.

Rucksacks

The first choice that needs to be made is between the conventional top-loading rucksack with side pockets (still probably the best for expeditions) and the newer- style 'travelsack'. The travelsack is a hybrid of a rucksack and a suitcase in that it has a zip that runs all the way around, allowing you to expose everything inside, a concealing flap to hide away the back harness and straps when they are not needed, a grab handle and shoulder strap for ease of carrying and, more often than not, they will come equipped with a detachable daysack. Travelsacks are extremely practical, but are inherently more expensive than traditional rucksacks because of the extra features.

It is very important to try on packs before buying one. There is a fantastic array of back systems and, as our backs are all different, the only way of finding out which one works best for you is to try a variety on.

For lightweight backpacking, choose the smallest pack you think you can get away with and check with the retailer that you can exchange it for a larger version if you really cannot get everything you want into it. Starting with the smallest is the best way to restrict yourself as there is always a tendency to fill space.

When it comes to rucksacks, two things are important from the outset: size and a capacity for being waterproof. Almost any size of sack you might want is available and (whatever the manufacturer may say to the contrary) none of them are fully waterproof. The capacity of a sack is measured in litres. A small day pack weighs in at about 25 litres. General, all-round sacks come in all sizes from that capacity upwards, culminating in one sized at 75 litres. One of these will allow you to manage anything, even mountaineering (at a push), but you pay a price for the facility. Having 75 litres to play with gives you a terrible urge to fill up all the space, even for summer camping in the lowlands.

Restricting yourself to packing what you need rather than what you have room for takes discipline. Because of this, some people prefer a 65- or even a 50-litre sack. Moving upwards from 75 litres, there is almost no end to the packs available, but the higher you go the more specialised the use: for expedition travel overseas, perhaps, or for humping all you need up to a base camp from which you intend making sorties with smaller loads.

When you look at the vast array of rucksacks on the market, you will find that fashion dictates two things. First is the anatomical, internal frame system. External frames are considered fuddy-duddy now, though the internal frame is not the all-round answer to carrying loads. The second (and far less valid) fashion is for adjustable harnesses. Try, if you can (and it gets harder every season), to avoid these. There are more fiddly bits that can go wrong, usually at an awkward moment (mine gave way halfway up the ascent to a glacier); and as your back should not be due to change shape significantly for the next 30 years, you may as well save yourself some bother. It is better to settle for a sack that is fixed at one size and just happens to fit you.

Something that has always been a very important asset to a rucksack is a hip belt. When walking, the hip belt transfers roughly 60 per cent of the pack weight to your legs, leaving only 40 per cent for your more delicate shoulders and back. Therefore any rucksack you buy should have a wide, sturdy, and very well padded hip belt. That thick padding should also appear at the shoulder straps. Thin bands will cut off the circulation, giving you the sensation of having two useless and heavy ropes dangling from your shoulders instead of arms.

After you've accounted for these important criteria, the rest more or less comes down to personal preference. If you are organised in the way you pack, a one-section rucksack is simpler and more effective. It is an advantage if your pockets can be detached, but having them fixed saves a bit of weight. Some harnesses leave more room for air to circulate between you and the sack. If you hate getting hot and sweaty as you walk, try for one of these.

When you buy your pack, enquire about the repair service. Well-established manufacturers such as Karrimor and Berghaus give excellent service, often without charging. Some will even give a lifetime's guarantee, though I can never work out if this applies to the life of the sack or the life of its owner.

Boots

Leather, suede and fabric are the materials most commonly used to make boots. Leather and suede are more breathable, durable and adequately waterproof - if well taken care of and treated often with a water-repellent substance.

Fabric boots, however, lend themselves better to the backpacker in that they are lightweight and have a more stylish, 'trainer' look and feel as far as general use is concerned (not every day is spent trekking). More often than not, they have a breathable and waterproof membrane. The waterproof function is excellent and needs little maintenance, while the breathable part tends not to work too well in hot, humid conditions. 'Breathable', in this context, seems to mean 'in comparison to wearing plastic bags on your feet'.

The modern answer is the cross-hiking boot. These provide a cross between the weight and comfort of a trainer with the sole and ankle support of a walking boot. The emphasis is on breathability and quick drying and, in conjunction with this, there is now a new generation of waterproof socks. This means that, when the need arises, boot and sock can be worn together and although the boot will get wet, your foot won't.

As with rucksacks, it is imperative to try on boots, and all feet are different. What suits one person may be wrong for the next. If you need to make several purchases within the shop, deal with the boots first so that you can keep them on in the shop for as long as possible while sorting out the other products. This will give you the chance to live with them, albeit for a short while, before making your final decision. Once you take your boots home, walk up and down some stairs while wearing them at least a dozen times before committing yourself to wearing them outside as, once you have done so, you will not be able to exchange them.

Leather is still the best for serious trekking. Spotting a good leather boot is fairly simple. As far as possible, it should be made from one bit of leather. The stitching is double, sometimes triple. The ankle is well padded to give comfortable support. The inside of the boot is lined with soft leather, and there are no rough seams around the heel. Feet tend to blister in disapproval of poor design.

Check the weight of several different pairs. It costs you energy to clump around with a heavy weight on each foot, and you may well decide that the terrain you usually walk on is not demanding enough to require such solidity.

If you intend to use your boots with crampons, however, you will need a fairly rigid sole. If you intend to go front pointing you will need a boot with a steel shank in the sole. For the common walker, though, these should be avoided as such boots become very heavy and uncomfortable to walk in over any great distance.

Traditionally, two pairs of socks are worn with boots, and some celebrated old-timers even wear more, choosing oversized boots to compensate. However, modern thinking says that boots are not as uncomfortable as they used to be and one pair of loop stitch socks is quite enough. So unless you suffer terribly from cold feet, prepare to try on your boots with just one pair of thick socks. With the boots laced up, rap the heel on the floor and check to see if you can wiggle your toes freely. If you can, the boots are not too tight for you, the blood will still circulate and you should be free from the horrors of gangrene and cold toes.

Cooking and eating

For this pleasant pastime you will need a stove, something to cook in, something to eat out of, something to eat with and (very importantly) something to carry water in.

A water container should hold between one and two litres and can be of any shape or design that takes your fancy. The solid plastic army types are the most robust. The thin aluminium ones are lighter but more fragile. Modern bladder-type bottles are excellent and take up no space in your luggage when not in use. They come in various sizes, up to 4 litres. The best of all of these is the US Army two-litre bladder with insulated cover, belt clips and shoulder strap. One rule applies for all water bottles, though. Put anything other than water in them and they will be tainted for life.

The essential part of the 'something to eat with' is a general-purpose blade. This will cut up anything you want to eat into manageable portions as well as whittle sticks and slice your tongue open if you lick it once too often. Beyond this, you only need a spoon. Anything more is redundant. Save the weight by cutting down on the number of utensils you take rather than by using flimsy 'camping' ones that bend the first time you use them.

For those who are into time and motion, what you eat out of is also what you cook in. Those who find this idea displeasing will know best what they want. However, when you look for a cooking/eating billy, make sure of two things. Firstly, it should have a good handle (preferably one that will not get too hot to hold while cooking is in progress). Secondly, it must have a close-fitting lid. This, too, must have a handle, allowing it to be lifted on or off or be used as a frying pan by those terrible people who can suffer fried eggs and bacon for breakfast.

There are many styles of billy available to choose from. I use a one-litre 'paint tin' type because I like the shape and enjoy hanging it over wood fires. Others choose the rectangular army-type mess tins. These fit nicely into the side pocket of a rucksack and can be filled with snack foods and brew kit.

Now let us look at the more complex subject of stoves. The choice here is between solid, liquid or gas fuels. Solid fuel comes in blocks that resemble white cough candy. A packet fits neatly into the metal tray that you burn them in. The whole affair is little bigger than a pack of playing cards. The system is foolproof since you merely set a match to the blocks and add more for extra heat, or take away for less heat. The fuel is resistant to water, though you may have trouble lighting it if it is damp. Its main drawback is that it does not produce an intense heat and so it is slow to use. It also produces noxious fumes and so should not be used in an enclosed space.

Moving on to liquid-fuel stoves, your choice increases considerably. Most simple of all is the meths burner. Here you have a container into which you pour meths and then set fire to it. The more sophisticated (and expensive) sets have a windshield built round the container, and which also neatly holds the billy. Again the design is foolproof. Its advantages include a clean-burning flame and quite a range of burners, from basic and inexpensive to high-tech and costly. However, the fuel is relatively expensive and may be difficult to get hold of if you are off the beaten track. Furthermore, the rate of burn cannot be controlled. The choice is simply on or off.

Still in the liquid fuel range, there are the pressurised burners that run on either paraffin or petrol. The burner for paraffin is the well known Primus stove. Though it is a relatively complicated device, compared with other stoves, it can be readily mastered. Once burning, the flame is intense and efficient and can be adjusted to give various rates of heat. As a fuel, paraffin is cheap and almost universally available. The disadvantages of pressurised paraffin are that a small amount of a second fuel must be carried to prime the stove, which will also need some maintenance. However, Primus stoves are known in most parts of the world, so spare parts should not be too much of a problem.

An alternative to pressurised paraffin is pressurised petrol. Again, this type of stove is quite complicated and needs occasional maintenance. Furthermore, it usually demands to be fed unleaded petrol, so buying fuel could present problems. Like paraffin, however, it burns hot and fast, heating quickly and efficiently. Petrol and paraffin also produce noxious fumes and both should be used in a well-ventilated space.

Gas stoves are simple to use. They are relatively cheap to buy but are expensive to run. They burn cleanly and the flame can be controlled, but when pressure runs low the flame stays stubbornly and annoyingly feeble. You can usually find somewhere to buy replacement canisters, but in out-of-the-way places the cost will be high. The little Camping Gaz canisters that are ubiquitous around Europe are difficult to find in the Third World and you are not allowed to take them on planes. Unlike paraffin, gas is not an everyday fuel in most places. Using gas stoves in low temperatures is inadvisable as their performance drops dramatically.

As with most areas of equipment, there is now a stove to beat all stoves. This is the multi-fuel stove. It can run on any type of liquid fuel you care to feed it, including (apparently) vodka, should you be so inclined. It comes with an attachment that screws directly into a regular metal fuel bottle, and so the burner itself has no fuel reservoir, making it much lighter and smaller than conventional stoves. The fuel runs through a hose to the burner and will be subject to frequent blocking if using poor-quality fuel, so constant maintenance is needed. Should you be interested in buying one, be prepared to spend a lot.

Once again, compromise is often the solution. You will generally find that a pressurised paraffin stove is the tried and trusted one used on most formal expeditions, and is the general favourite of many. I find solid fuel a handy last resort to have available when you are travelling light and having difficulty lighting wood fires. Gas fuel is simple to use in all but extreme conditions. You pays your money and you takes your choice.

Last thoughts

With so much wonderful equipment around, it is easy to get carried away and want to buy the best of everything: a large rucksack to carry a five-season down bag with a Gore-Tex bivi-bag, a 'superstove' and a geodesic dome tent. Thankfully, most people's pockets refuse to support such notions.

In reality, if you think carefully about the use to which your equipment will be put, you will often find that the 'best' is not suitable for you and that you are just as well off with something cheaper. Then, when your style of travelling or camping does demand the best, the expense becomes worthwhile and supportable. So do not end up being parboiled in a five-season sleeping bag that only ever gets uses in summer. The money could be better spent elsewhere.