these are very bulky, not suited to hiking
before 1st use, they should be left out in the sun for 45 minutes with the valves open to help undo the vacuum sealing process they go through (or left open overnight)
should be stored flat with valves open to avoid memory foam issues otherwise it will take longer to self-inflate
self-inflation for many mats only gets to around 90% inflation so if you want it more firm you will need to pump some extra air in (but doing so on cheaper mats may make them more bouncy)
avoid inflating with moist air as this may decrease the life of the laminate - delamination is generally the most common defect in self-inflating mats
cheaper versions of these tend to be unbonded - ie the outer is never bonded to the foam and thus the air can distribute away from your heaviest part - your butt - in this case, the less air you have in there the more even may be the support - consider sleeping with one valve open! Over-inflating by blowing air into them just tends to exacerbate the issue.
“3D” design means they have stiffened side walls that wont collapse easily and this also makes them easy to join together using straps.
the wider ones in particular can be more difficult to roll up tightly
with the valve open fold it into thirds then seat on it for a few minutes until the air is released
then open up and do a large roll up, again with the valve open then sit on it again to deflate more air
now, if it is a double, fold it in half, (an assistant can keep the valve end folded over while you roll it tightly)
then roll it up as tight as you can, finally, lock the valves closed
single stretcher bed mattresses
folding foam mattresses