Brake rotors wear quickly. Some '91 owners have reported minimum tolerances on rotors before reaching 60k miles. Rear brakes may wear faster than front.
A number of owners have reported VERY uneven wear on the inside pads. In some cases, 1/2 wear on outside pad, with the interior pad completely worn out at < 35k miles. Be sure the slide bolts are well lubricated with a high temperature grease.