Store thermometers are interesting. I always just compare them and pick one that agrees with most of the others on the rack. There'll always be an oddball. Don't bring it home, ha. Now if you're into critical temps, you can swill your new thermometer around in a glass filled with crushed ice and water and it should read 32F. Or a pan of boiling water and it should read 212F. You'll have to pay for it first. I used thermometers a lot before I retired, and I'd periodically test mine (and adjust, if needed). Of course that was back in the dark ages. Now they probably have something that they point and it speaks the temp to you.
Tire guages? Never gave them much thought. Now you've got me wondering. I've got three or four and I'm gonna compare them, not that I'll know anything when I'm done.