The list below shows drivers who would benefit from having their brakes checked closer to the 20,000 mile mark. The less stress you put on your brakes, the longer you can go without a brake service.
Driving on hills with lots of sharp turns.
Urban stop-and-go driving (versus highway miles).
Using inexpensive/unreliable brake pads and other brake system components.
Driving in mountainous country, where downhill braking is necessary, may also add wear and tear to the brake pads.