The average life of brake pads is 30,000 to 70,000 miles. A number of factors affect the point at which brake pads wear out. Pads are made of various materials for different types of braking systems.
Friction, pressure and heat all affect brake pads. Pads should be checked during oil changes. Mechanics use gauges to test the wear on pads and to predict the remaining life. Some brake pads also have clips that make noise when they wear beyond a certain level. Signs of brake pads becoming too low include loss of power when brakes get hot and pulling to one side while braking.