If you let your brake pads wear down, they get hotter and they ruin the rotors. When they ruin the rotors, that becomes a big job. Most manufacturers put little brake squealers on there. They’re little metal clips and when the brake pad gets too close, that squealer comes in contact with the rotor. So listening for noises is very important. But replacing the brake pads early enough will save the rotors. If you save the rotors, it saves money.