Some people ignore the warning signs and keep driving long after the pads are completely worn out. When that happens, metal brake components will grind on the rotor, damaging it enough that it needs to be resurfaced or replaced. Rotors can also warp or crack, in which case they'll need to be replaced.
Brake calipers also wear out over time. They can develop leaks or the caliper pistons can freeze open or closed – either way it's not good. When this happens it's time to replace the calipers. A thorough brake inspection will reveal worn bearings or seals as well.Learn more at NAPAautocare.com/preventative-maintenence/