Help me understand cots. Do any/all of the ones provide adequate side-sleeping comfort without a pad (foam, ThermaRest, air mattress)? I’m intrigued, but probably haven’t used one since kindergarten, and I’m hesitant to pack both a cot and mattress. When I travel solo I use an Exped air mattress; with my wife we use a pair of large ThermaRests which are pretty bulky. On the other hand getting off the ground and not dealing with inflating and especially deflating, sound good to me.
My personal answer to your question is a firm no, especially if you're older and need cushioning for your hip and shoulder joints, or if you're on the heavy side. The combination of a good mattress and a good cot will
double your comfort compared to either one alone, in my opinion.
Advantages of a cot: It gives you a feeling of being suspended, you're off the bumpy ground, it's very easy to get up from a 15" cot (same height as a sofa), and you can store things under it.
However, a good cot has a very tight top---drum tight---so it doesn't stretch and sag over time. That tight top is hard and doesn't provide any cushioning. Hence the need for a mattress.
My favorite mattress is the Exped Synmat 3D-7 on either the Helinox Cot One Convertible or the Camptime Roll-a-Cot. I recommend these items with no reservation, sight unseen. If you're concerned about pack size and/or weight, the Helinox has the edge over the Camptime. The Convertible cot can be used in a lower tent (like a 2P) or a taller tent with the leg extensions (minimum tent height for a 15" cot is about 52"; 60" and over is better). The Camptime can only be used in a taller tent.
Does your current Exped mattress use the pumpsack? I recommend the small yellow sack as the large brown sack is harder to use (for me). It takes 3.5 fillings of the yellow sack to inflate the mattress. The most comfortable way to do it is to roll the mattress out on a picnic table if available. Total inflation time is about one minute. I think that's reasonable for all the comfort you get. Deflation and rollup of the Exped Synmats takes one minute or less. Cot assembly takes about 5 minutes. Total assembly time for a great night of sleep: 7 minutes.
Now, if you're talking about the Exped Megamat, that's a monster that I gave up long ago because a Synmat on a cot is more comfortable than a Megamat on the ground, and much easier to deal with.
The Exped Synmat 3D-7 is 2.8" thick. With a cot, you don't need anything thicker than that. Thus you can save weight and bulk on the mattress by using a cot.
Here's the total package:
Helinox Cot One Convertible (including legs) 5.9 lbs + Exped Synmat 3D-7 MW 2.8 lbs =
8.7 lbs. The packed cot is 5.5" x 21.3"
Camptime Roll-a-Cot Wide 10 lbs + Exped Synmat 3D-7 MW 2.8 lbs =
12.8 lbs. The packed cot is 6" x 37". This shows the space-saving advantage of the Helinox cot, but you pay a lot for the smaller packed size.
What about a foam mattress? Not needed with a cot, not as comfortable as air, and air never packs down like foam.
What about a combination foam and air mattress? Again, not needed with a cot. Air is all you need and it weighs . . . nothing!
P.S. Exped changes the names of its products often. The above are the old names.
PP.S. I've slept on my Exped Synmat 3D-7
every single night for the last 5 years, both camping and on top of my mattress at home. That's how comfortable and durable it is. The mattress can go 6 months without needing to top off the air.
Why am I a cot and air mattress fanatic? Because those two developments of modern camping gear allowed me to return to camping when I had severe arthritis in my shoulders and hips. Now camping is just as comfortable as sleeping at home. Really.