How do you know when your brakes are bad?

Several things to watch for. Your brakes will sometimes start to stutter or pulse as you apply them. Occasionally you will hear a noise like a grinding or a squeal. With any luck, it'll be the pads wearing out before the rotors get damaged, but that''s not the way things usually happen. People have a tendency to let things go until more work is involved. If addressed soon enough, most rotors can be turned and used again, If left too long without attention, you will need to replace the pads, the rotors, and sometimes even the calipers, so...best to take care of things as soon as you can.