Brake pads generally last between 30,000 and 70,000 miles although shorter and longer life spans exist. Semi-metallic brake pads typically have a life span of 30,000 to 50,000 miles. The life span of brake pads depends on the material used in the pad, whether the car has an automatic or manual transmission, and the driver's braking style.
While brake pads made of non-metallic, organic fibers produce the best stopping power, they also have the shortest life span. Most brake pads in use are semi-metallic. In these pads, organic fibers are combined with steel, copper or iron to make a brake pad that is tough and more heat resistant than other types.
Brake pads must be checked regularly. Whenever a driver hears a squealing noise while braking, it is an indication that the pad has worn down to an unsafe level and must be replaced as soon as possible. Continuing to drive once a brake pad needs replacement is dangerous and can cause serious damage to the brake rotor. A car that pulls to one side while braking can be a sign of brake pads that have worn down unevenly or of other serious brake damage. When pushing on the brake pedal produces little reaction from the brakes, it is time to get the brakes serviced.