On my HCH, I keep the pressure at 44 psi all around. I find that the pressure stays nicely for several weeks, but as soon as a strong weather system passes through, I lose pressure. For example, I checked the air pressure two weeks ago, 44 all around. Yesterday I checked again (after the fierce rain and wind storms) and the pressure was down to 40. The temperature was 20 degrees cooler than two weeks ago (that would account for 2 psi).
So, my belief is that there are many factors that could cause variance in the pressure. One should check air pressure more frequently than once a month, depending on use. For my 700 miles per week, at least one a week is probably a good idea. Now, putting that idea into practice...
