I have only done it a couple of times. Usually I change pads before the rotors warp. Or if the warpage is bad, I change the rotors and don't even think about having them turned for the same reasons as several posters in this thread. The warpage will just come back anyway if not be there from the start.
These days rotors have such low tolerances that you can't hardly cut them down unless they're almost new. My Torino I could probably cut them several times. The Durango, not so much. I think it was the 97-99 Malibu that was one of those that came out with the real thin rotors. People were ticked that warranties didn't cover warped rotors, and they warped fast. I think they fixed that in 2000 and the 2000 model rotors are retroactive to the older years. I'll have to check on that sometime.