I have found that as the car grows older, sometimes the calipers tend to stick. This is especially a problem as the pads wear and the caliper piston has to travel farther out in the cylinder bore. When they don't retract properly, it eats the pads. An easy way to tell if they are sticking is to feel the wheel after a short run. If the wheel is really hot, or if you notice one side is much hotter than the other, you may have this problem. My 1990 400 completely wire out my right rear pads in about 3 months. I was able to clean it up they work okay now, but I don't like that stuff. I have a new caliper in the trunk and will replace it this week. I paid $94 for it. Dealer wanted $365.