It's so rare here for the air hose at the service stations to have a pressure indicator of any kind that I neglected to mention that for consistency each car should have its own good quality gauge.

Total agreement on using your own, especially when you get home and check after having new wheels mounted or otherwise serviced "professionally." The gauges used by many service shops are so far off that you'll probably want to adjust things (although I've identifed a couple that are reasonably reliable).

Really good gauges are pretty cheap now, so it's not too necessary to use a "nasty" one. Good digital ones can be had for less than a cup of Starbucks. They should be tossed and replaced when the seal rubber hardens enough to make them "fussy" in use; but of course I've got a fistful that are too good to throw away just yet. I do the replace - just haven't had the heart to do the toss. Some of the old ones, still usable and accurate, have to be at least 50 years old.

John