Your cars brakes are one of its most vital features and will need replacing during the lifetime of the vehicle as they wear out. The main components that suffer wear are the brake pads and disks. The disks, usually cast iron, are attached to the axle. The brake pads are pressed against them when you apply the brake pedal thus reducing the cars speed. Because the weight of the car shifts forward under braking, the front brakes do most of the work. You may notice that the rear brakes appear different to the fronts.
Because the rears do less work, they can suffer corrosion which is not cleaned off during braking. This happens more often in smaller or seldom used vehicles. You can combat this corrosion by applying heavy braking occasionally, when safe to do so. The disks will wear over time and will need to be replaced in pairs when the manufacturers specified minimum thickness is reached.
Braking on long downhill runs will over heat and possibly distort your brakes. Avoid this by selecting an appropriate low gear. Avoid sitting with your brakes applied after heavy braking as this may also damage your brakes.