Have you ever seen someone checking tire pressures?

I would always check mine before leaving on a trip. After that only if after visually checking them one "did not look right". I know, they can be a little low and still look ok.
Installed a TPMS and don't have to bother with the air gauge any longer while traveling. Although I do still use the gauge before we leave on a trip just to verify the TPMS is reading correctly.