Axe- you should check the operation of your rear brakes. I've never heard of pads "looking new" at 90,000 miles. Sounds like they may be out of adjustment or the proportioning valve may not be set up right.

In addition to pad thickness, it is important to inspect the pads to make sure the material has not "crystalized" or hardened (from heat) into a low-friction material. You'll also want to inspect the drum for wear and damage.

This "inspection" should be done regularly for safety's sake.