Brakes are plain and simple; brake pads should be replaced before they are worn out. If you have a brand-new vehicle, recommend the rotors that came on the vehicle be replaced on your first brake job. Thereafter, continue to replace your rotors with every other brake job. If you are coming to a stop and you feel a pulsation in the brake padel, there may be a concern with your rotors and replacement would be recommended. Also keep in mind that pulsation can be felt in the pedal if there is a concern with your rear rotors.