My fancy round tire gauge**, with big rubber bumper, that I paid a full $17 for on Amazon only 2 years ago, only used 5 or 10 times, stopped holding its reading. Darn. But googling found a 3 minute video*** that said how to easily fix it.
**First time I did this, it sort of held the reading. That is, for a second or two and then it started going down. After the second time it seems to hold it for a minute or two. Maybe longer but there's no reason I need longer.
The gauge is guaranteed for 10 years, it turns out, Says so in the Amazon ad itself.