Brakes are very important part of the car, and no risk should be taken in the maintenance of this part. The mileage of the car will vary according to the usage of car. Similarly, the brake life will also vary according to the usage as a friction material will be pressed against a brake disc or drum so that the vehicle can be stopped. If the vehicle is used in rural places, then the usage of brakes will be less when compared to urban the areas. Unfortunately, there are no specific symptoms or schedule that states the brake has to be replaced.
One has to take care of it during each servicing scheduled. Usually, tires will be checked and replaced every six months according to its usage, and it will be a good time to have a look at the brakes too. Usually, the thickness of the pads will be noted along with the other brake hardware in order to know the exact condition of the brake. In recent cars, there is a wear sensor placed on the sides that indicate the requirement to change the brake. A screeching sound will be produced by the sensor when the driver applies the brake it happens as the sensor will scrape on the brake drum.
Even though if this sensor is not available in the vehicle there will be squeals, squeaks and grinding sounds from the vehicle if the brake drum has worn out completely. If the noise is very less, then it can be stopped by minor cleaning but if it often occurs, then major repair is required. In some cases, even though if the brake is applied at a spot, the vehicle might stop after crossing some extra distance. This clearly shows the need for brake change, and it is a very dangerous symptom.