If you can get to a BJ's gas station they have the future of air hoses installed. You tell it what PSI you're shooting for and it checks the tire pressure as you're filling and stops when it gets to that target. It's one of those obvious innovations you wonder why it wasn't at every air hose years ago.

I usually just look for a 7-Eleven for they don't charge for air (they aren't listed on the site).