Sleeping pads come in two main types: closed foam and air pads. Closed foam pads are virtually indestructible and affordable. Air filled ones, again, pack down smaller and the thickest models are superbly comfortable. The choice of a sleeping pad depends heavily on whether you need lightweight performance or lots of loft and insulation.
Both the most compact and most warm pads are air pads: uninsulated ones are super compact and suitable for summer use, while insulated ones range from three season use to winter pads. We recommend using a pump to inflate an air mattress, which helps you avoid introducing moisture to the air chambers.
Self-inflating mattresses pull most of the air in by themselves: there's a layer of foam that starts to return to its original shape once you open it up and open the valve. After a certain amount of time you just close the valve, or blow a bit of extra air before doing so.
When using air pads or self-inflating pads, it's worth while to spend a bit of time preparing the area: as an air pad can get punctured, you want to remove all sharp objects such as shards of glass, sharp pieces of stone or even pesky pine needles. The floor of a tent or other shelter gives a bit of protection, and many choose to use a super light foam pad under their air pad for maximum security.