Before TPMS you filled your tires to some nominal pressure (usually what the door jamb sticker said) and off you went, likely months before you checked it again if you checked it at all. Probably didn't get attention unless something was evidently wrong. Gee that tire looks low. Who knows how long you'd go that way before noticing.
Post-TMPS now I see one tire is a PSI higher or running warmer than the others. Kinda like a man with 2 watches now, going back and forth tweaking tires day and night squinting at the gauge to see which side of the tick mark from perfect they are. I've reverted to my former mode of tire maintenance, set it and forget it unless something actually happens that requires intervention. The TPMS is handy for verifying you didn't have a leak overnight and to warn of serious over or under pressure but for the most part I ignore the numbers. I set them all before a trip and unless something fails they will be fine for a few weeks at least. I put in an extra 10lbs or so when I winterize, come springtime I bleed down when cold to operating pressure and that usually carries me through half the summer. Back when I rode my scooter I'd tweak up and down a couple PSI to balance stiffness and contact area for going through twisties but a 90PSI tire on a delivery truck has no such performance subtleties.
Mark B.
Albuquerque, NM