Just replaced the pads, for the first time, all the way around at 90k (still had 40% on the fronts...backs were due) and my rotors were in good shape...no warping at all. 90k on a set of pads is a record for me too.

 

I have the originals on mine at 172,000. They have been cut once, and I am on the 4th set of Wagner Severe Duty pads. The rear rotors were replaced with drums when I changed the axle to a 2500 Dana 60. Got a shock when I replaced the drums last spring they were $112.00 per drum at autozone.