front rotors warp- vibration while braking

I drove this car for about six years, and wound up having to replace the front rotors three times, most recently this spring.

I never wore out the pads, but I would get a wicked vibration every time I pressed the brake pedal. Replace the rotor, and it goes away. I DO live in a hilly area, but I don't particularly ride the brakes, just enough to slow to the speed I want, then downshift if I need to. Seems these rotors tend to warp easily (according to a local mechanic "oh ya, those cars eat rotors")