Brake pads use a very simple equation in order to stop your vehicle. By converting the kinetic energy of your moving vehicle into thermal energy (by way of the friction created by contact with the discs), the brake pads are able to facilitate a smooth and easy decrease in speed. The pads, when in contact with the discs, heat up and begin to transfer a little bit of their material onto the discs. This heated material begins to "stick" to the material on the brake pads, causing a more efficient stopping power. Brake pads are designed to wear out over time and typically last anywhere from 20,000 to 50,000 miles, depending on driving style and application.