Modern disc brakes are far superior and better than the older drum brakes in many ways. They offer better stopping power, and can be equipped with antilock technology to increase your safety. However, they do have a few drawbacks. One of those is the draw backs I thst the pads wear out more quickly than shoes (pads are used on disc brakes, while shoes are used with drum brakes). Thus having said that, if you’re experiencing unusually fast brake pad wear, there could be an issue.

How the brake pad system works:

Your brake pads are the point where all the activities happens with your system. They’re prone to wear and tear through from operation. Understanding how disc brakes work isn’t all that hard, and the basics of the system are pretty simple.

A standard disc brake is composed of a caliper, two brake pads and a rotor (per wheel). Fluid is transfered to the caliper from the master cylinder when you depress the brake pedal. A piston inside the caliper is activated, and the caliper then squeezes the rotor between the inner and outer brake pad. This action slows down your vehicle. It also generates friction, heat and lots of wear on the material of the brake pad.

Over time,the brake pads wear out. That’s only natural. You have to change them periodically. The exact frequency will depend on your driving style and habits. For example, if you do a lot of stop-and-go driving, you can expect your pads to wear out much faster than a driver who does mostly highway or goes on an interstate driving.

So if you’re noticing abnormally fast brake wear, there could be some problems.

Common reasons why this happens:

Driver Error: The single most common reason for abnormally fast brake wear is driver error. This is most usually visible with “two-footed” drivers who use their right foot to work the gas and their left to work the brake. These class of drivers tend to leave their left foot resting ever so slightly on the brake pedal. Understand that ANY pressure on the pedal engages the brakes even so slightly. So, even a small amount of pressure on the corner of the pedal is enough to put the pads in contact with the rotor while the vehicle is moving. This eats through pads very quickly. It’s also generally followed by “bluing” of the rotors, which is a sympton of overheating.
Corroded Slide Pins: The caliper must be able to slide smoothly and evenly at all times. If the slide pins are corroded (most common on old vehicles, or flood-damaged cars), the caliper may not slide out evenly, leaving it placed slightly off center. This places part of the pad in contact with the rotor at all times and will lead to premature pad change.
more:http://www.automobileglobe.com/what-makes-brake-pads-wear-out-quickly/