A bit late, but I'll share my $0.02 anyway...

I use takeoff tires, so I usually wind up going through 2-3 sets in a season. Every time I take the wheels to the shop to get tires mounted, I clean them up and check them over on the outside. Once the first set of tires are dismounted, I inspect the inside of the wheel while the tire guy is working on the next one. it takes the tire guy just a bit longer to run through the set since they have to mount/dismount each wheel an additional time, but if you're nice end explain what you're doing, they're always willing to help out.

Checking the inside of the wheels like that actually saved my butt last year. I had a 5Zigen wheel that cracked on the inside edge of the rim, but it wasn't visible during my regular driveway inspection due to the thick powdercoat on the shiny side of the wheel. I could only see it on the inside part while the tire was off.

FYI, those wheels were ~5 years old and haven't seen any major excitement, but they have spent a little bit of time sliding through the grass at the local tracks. Nothing out of the ordinary for wear and tear.