I've been riding 100PSI on any tire I put on my bike. I seldom have flats. When I do, I have 2 new tubes in my seat bag along with my bike tools. Usually I give my flat tire to a friend who will use it on his rides. I'm too lazy to fix a tube.

I do suggest that you always carry 2 tubes with you. Also, if you put "baby powder" on them, it will make it easier to put on the rim.