Depending on the type of car that you drive and your driving habits, your brakes can last up to 30-40,000 miles. In some cases, brakes may begin to fail earlier, either because the parts used were substandard or because of how the car was driven. Brakes can also last for longer, but however long it's been since your last brake change, worn-out brake pads should never be ignored. If that time is coming for your car, then there are several things you should know so that you can make the right replacement decisions.

Brake Pad Thickness

Although many people wait until there are noticeable drivability symptoms or the brakes have begun to squeal, there is a more scientific way to determine if your brakes are in need of replacement. As a general rule, your brake pads should be replaced once the pad thickness has fallen below 3mm. This isn't something that you can easily check without raising the car off of the ground and removing the wheels, so it is a good idea to have your pad thickness measured whenever your car is in the shop for other types of work.

Low Pad Thickness Can Cause Additional Damage

Replacement is usually recommended at 3mm to prevent additional damage from occurring as a result of worn pads. If your pads begin to wear down beyond this point, the backing plate that the friction material is installed on may start to make contact with the rotor. Once this happens, it can cause damage to the rotor's surface. Light damage may be correctable with resurfacing, but if this type of wear is allowed to go on for a long period of time, then the rotor will almost certainly have to be replaced.

Your Rotors May Need to be Replaced

Many owners are shocked to hear their mechanic recommend a rotor replacement when they simply want to replace the pads. Rotors do not always need to be replaced along with pads, but some manufacturers do recommend that the rotors be changed with every pad change. In most cases, this is because the vehicle in question has an extended brake pad change interval, and it is likely that the rotor will be worn by the time the pads are replaced.

If a rotor replacement isn't strictly recommended, then your mechanics will check the thickness and condition of the rotors. If the surface of your rotors has become gouged, then a resurfacing will be recommended. The rotor thickness will be measured at this time as well, and if it is found to be too low, then the rotor will require a replacement rather than resurfacing.

Remember that both your brake pads and your brake rotors are considered wear items. While brake pads generally wear faster, there will come a time when both need to be replaced. Having a brake replacement done as soon as it is necessary is the best way to keep your car and its occupants driving safely.