doing brakes for the first time

i purchased my c320 last summer, and now it's time to perform my B service. i have changed my oil, air filter, cabin filter, checked my fluids, and have taken a look at my brakes.

i have never worked on my own brakes before, but am confident that i will be capable of servicing them myself. i do, however have a few questions.

given that i don't know when/where my brakes were last serviced... can i rely on the pad sensor to warn me when the front pads need to be replaced? i am assuming (maybe incorrectly) that if the sensor is missing, or if it is faulty, that the FSS would have already complained.

also, the rear rotors may be questionable, but i am not certain how to tell if they should be replaced. there are some visible scratches along the surface, but it is still very smooth to the touch. i don't feel any pulsing in the brake peddle, and they are quiet, so i do not think there is any warping. can someone please offer me some suggestions? i have seen differing opinions on this board, some say replace rotors with pads, some state their dealer recommends that the rotors are replaced with every other pad replacement.



thanks for reading