I think it just happens, especially if you are heavy on the brakes. I just got my front ones replaced not to long ago. Only advice I can give is try braking not as hard and start sooner. It seems to work well for me. The only reason mine got warped the last time was because some idiot in a van slammed on his brakes in front of me for no reason, and we were on a highway. The car shook ever since. Feels good to have a shake free stop.
