Replace brake pads & rotors at same time?

My brake pads light of my 325i came on the other day. About 15,000mi ago I had all brakes and rotors replaced. My BMW dealer claims that they have to replace the pads and rotors at the same time and that I can't just replace the pads. This seems a bit strange to me. Any advice would be greatly appreciated.

Nice sales job, however if your rotrs are not warped they do not need to be replaced. Also, did you replace brake pad sensors when replacing the brake pads? If you have the prompt, then replace the sensor/s as well.

Yes, I had the sensors replaced then as well. I am aware of the sensors that these need to be replaced every time. I brought the car in this morning and told them I don't want the rotors replaced. Of course I got the whole sales talk again. I just can't see how rotors would need to be replaced every single time. Does anybody know what the average life span is of rotors?

Thanks

Do not know about your 3 series but on my 1988 750 I replaced the first rotors at 75,000 miles and currently I have another 65000 on her with no problems.

rotors need replaced when ever thet wear too thin it is stamped on the rotor that is wy they are likyl recommending replacment because the goverment mandates that rotors must be replaced once they get too thin. as for average life that depends on driving stlye and type of driving (city or highway)

I'm at 65K miles, and still on the original rotors. Sounds like they're trying to get deeper in your pockets than they already are.

I do not replace my rotors unless 1) they are pitted, rusted, or otherwise damaged, or 2) I'm getting a pulsing in the brake pedal when the brakes are applied. While this symptom is usually called "warped rotors" or something similar, I've read that in most cases it's caused by a transfer of material from the pads to the rotor after a panic-like stop which leaves the rotors/pads hot and the pads in contact with the non-moving rotor. Whatever the cause, if there's no pulsing in the brake pedal, I leave 'em alone.