if you dont change rotors but only pads and sensor than make sure rotors are perfectly smooth and a meet minimum thickness with a digital caliper.Rotor has a minimum thickness spec stamped onto the hub in mm normally 18.4. I believe rotors start with 20mm Since the orginal rotors started with 20mm nominal, if you wear away 1mm of steel. Assuming that the replacement pads last about the same number of miles, you wll be down to 18.0mm(below the 18.4mm min). Might be prudent to change rotors even though technically speaking they are within spec.
also remember to bed in new pads.