Travelling in the Third World is not like a camping trip. You will find plenty of cheap food and accommodation everywhere, so you won’t need a stove, tent or sleeping bag,
There may be occasions where you would think a sleeping bag might be useful, in a cold room, sleeping outside (when it is warm), protection against insects, as a seat or cushion, etc., but consider the alternatives first.
Long underwear or other warm clothing will be fine in emergencies, on buses, trains, and cold hostels. A sleep sheet packs small, is light and easy to wash, and should suffice for all other times. Combine this with a plastic sheet, bivouac bag or poncho and you can replace a tent and sleeping bag.
If you do decide to take a sleeping bag then you there are certain things to look out for when choosing one.
Sleeping bag
For camping, cold climates, and trekking in the mountains, you can buy the most expensive, warmest bag you can find. But this will be way too warm to use in the tropics. It will also be bulky, heavy, oftentimes flimsy, as well as hard to wash and dry.
The new super-light synthetic bags are good, and one with the zips in the right place can turn it into a blanket for sleeping or picnics.
Down bags can sometimes be too warm (unless you are going somewhere really cold) and don’t perform well when wet. You also need to dry them properly after you wash them to maintain their insulating properties.
I use a 
Western Mountaineering ExtremeLite down bag. You can find a good selection of both down and synthetic bags at 
Blacks in the UK or REI in the US.
Using a sleep sheet (see below) inside your sleeping bag will delay the need to wash it for a long time.
Sleep sheet/Sleeping bag liner
Basically a sheet, made from either cotton or silk, folded and sewn into the shape of a sleeping bag. These are mandatory for sleeping in hostels. If you don’t have your own then you will have to buy one. A good substitute for a sleeping bag in warm climates.
I use a Lifeventure Advance Sleeper Cotton
You can read more about sleep sacks and buy them here
here
Bivouac sack
The waterproof version of the sleep sack. The cheapest are made of plastic, some are made of nylon, the most expensive are made of Gore-Tex and are like small one-man tents, some with built-in mosquito nets.
Mostly used as emergency shelter when hiking or mountaineering, but can be used when travelling to protect your sleeping bag (on the outside), for extra warmth, and as a replacement for a sleeping bag or tent in warm climates.
They are lighter and easier to wash and dry than a tent/sleeping bag combination, but can be colder and more cramped to sleep in.
In warm weather you don’t usually have to worry about the rain, just the insects. When I am sleeping out in hot climates I use a Bug Hut 1 tent from REI (shown left). This is an ultralight shelter that is fast to put up. It fits completely over your sleeping bag and the poles keep the mesh away from your upper body.
Hammock
A good compromise sleeping solution is a hammock. These are lighter than a tent and more comfortable to sleep in. I use mine for emergencies when travelling.
You would be surprised at the number of places you can use it. The best manufacturer and model I have found (and one that I own) is the Hennessy Hammock UltraLite Backpacker A-Sym (shown right).
Read more about hammocks and sleeping in them here.
Sleeping Pad
This is what you lie on when sleeping on the ground when camping. It both insulates your body from the cold and the hard, sometimes rocky ground.
They come in two basic types, the closed-cell foam type, which is thin and bulky which either rolls or folds up, and the inflating type, which insulates better and packs smaller, but is heavier and more expensive.
Therm-a-Rest (shown left) make the best of the latter kind. These are ’self-inflating’ (although they sometimes need help).
The lightest weighs just over 1 pound, (455g) but this model is also the shortest and least insulating.
Their construction means that they can get damaged on thorns and other sharp objects, and will stop working if they get punctured. They can be hard to repair (they come with a repair kit).
They come in a variety of sizes (long, regular, short lengths) and insulating properties (3- 4-seasons, for example). I have the Therm-a-Rest ProLite 4 Regular which is a 4 season, regular length (72″, 183cm) sleeping pad.
You can buy them from Blacks in the UK or REI in the US.
Pillow
Inflatable pillows can make it easier to sleep on a plane, train or bus. There are two types, one that fits around your neck like a collar and ones that look like regular pillows.
You can also buy a stuff-sack which, when filled with clothes, can make a good pillow, particularly the ones that are specially made for this that come with a cloth lining (turned inside-out when used as a pillow).
Check them out here. They come in two sizes, I use the 10″ x 20″ model for my sleeping bag stuff sack.
