When backpacking in September, 10 to 11 hours out of every 24 are spent in my sleeping bag. Work it out: dark at 8 pm, read with a lantern till 9, then it’s not light till 7am and sometimes too chilly till 8.
In my youth I could “die” for 9 or 10 hours at a time, but over the years I have become a lighter sleeper. In a tiny nylon tent that is usually on uneven or slightly sloping ground, I tend to drift in and out of sleep all night. Any running water, from a nearby trickle to a distant cataract, is plainly audible, you hear the wind in the grass, rain splatters or drums on the flysheet, and aeroplanes drone high overhead. Then there are the noises you cannot define (made by sheep, probably), that leave you laying there with the hairs raised on the back of your neck.
It took me some years to realise that much of my sleeplessness was due to the caffeine in the mug of coffee I used to drink after my dinner. Cutting it out made a big improvement.
Unless you are someone who sleeps like a log, it is important that to get a good sleep you are as comfortable as possible under your self-imposed limitations.
You must have a ground mat to stop coldness from the ground rising to your sleeping bag, this can be anything from a closed-cell foam one to a thick self-inflating one, depending on what you can afford. Don’t compromise on performance, for which some mats carry a tog rating these days, but at the same time choose with weight in mind, you don’t want to carry anything heavier than you can help.
A three-quarter length mat is lighter than a long one, the price is lower too, and I find one quite adequate. To compensate, I spread my fleece in the end of the inner tent that the shorter mat doesn’t reach, with a bit of the fleece tucked under the end of the mat to hold it in place (though it doesn’t always stay there).
I like a reasonable pillow, but I find inflatable ones a bit hard to sleep on, even when under-inflated, while they are additional weight to add to the pack (although there is one, the Flex Air, that is only 27g, that’s under 1 oz). No, I simply use what I already have, by folding my insulated jacket in half and pushing it into the sleeping bag’s stuff sack. Job done!
(Update, 2016: I have replaced my old synthetic insulated jacket with an ultralight down one that packs very small and doesn’t make much of a pillow, so I think I will be putting my fleece top in the stuff sack in addition.)
Sleeping mats tend to slide around on a groundsheet in my experience, particularly as I’m a side sleeper and turn over a few times in the night. It is prevented with a 3 ft x 1 ft roll of anti-slip matting bought in a hardware shop for a couple of pounds and laid under the ground mat. I position it so that some is under my pillow, too. To me, the benefit justifies the additional 95g (3.3 oz) weight in my pack.
Unless your tent has built-in pockets, think where you are going to put everything when you turn in for the night. You will no doubt want things like light, watch and perhaps water close at hand. Having them near is never a problem in a tiny backpacking tent, but you do not want to roll on anything and damage it in your sleep. The biggest problem for me is my spectacles, I am terrified of breaking them; my current solution is to balance them on my rucksack in the porch.