While on the road, I never mess with the air pressure (80 psi for my rig). When I return home, I deflate to 15 psi. Why? because it makes me feel all warm and fuzzy. On my 5th Airborne there is a white inflation line that marks the proper pressure after hitching up. As long as that white line is where it is supposed to be I don't bother checking because as someone else said above, the volume is very small and you will probably let too much air out just checking it. Then you will have to drag the pump out and start all over.