Your vehicle ,manufacturer has a recommended interval to inspect and/or replace brakes. Typically it may be every 20k-30k miles depending on your predominate type of driving style 'hard braking' or driving conditions 'stop and go traffic'.
If a rear wheel drive car your rear brakes will wear almost twice as fast as the front brakes, because more power is delivered to that axle, therefore more stopping power is exerted by the brake pads.
When applying braking more forces are exerted on the front of the vehicle, this is why vehicles fitted with only one set of disc brakes (superior to drum) use them on the front of the car, and why front brakes usually wear faster.
There are many local shops that will perform 4 wheel brake inspections for a small fee.
Hope this helps
A. J. Pierce
When should you consult a professional to look at your brakes?
''' Drip, drip, drip. First, look down where your car was parked after you moved out of a parking space. Are you leaking brake fluid? You’re checking for stains or small puddles of fluid that don’t look like oil or coolant. Motor oil will probably have a brown or black look and feel slimy to the touch. Coolant will appear green and more watery. Brake fluid can look like fresh motor oil, but it doesn’t have that slimy feel. You’ll need to get your hands dirty, but check those puddles. If you suspect you are leaking brake fluid, open the hood and check the reservoir (your owners manual will tell you where to find the reservoir) is it low? If you’re leaking brake fluid, consult a mechanic immediately. DO NOT DRIVE THE CAR! Without the proper amount of brake fluid in your brake lines, you will not have full stopping power. If you see a puddle of brake fluid, or your brake pedal feels spongy and low, tow it in to your favorite repair facility.
''' Squeal, squeal, squeal. If the noise from your brakes is constant, you probably have a problem. Consult a mechanic immediately. He or she will check the brake calipers, brake shoes, master cylinder, etc. The cost of the potential repair will vary according to the problem, make and model of your car.
''' Scrape, scrape, scrape. One sound you should hope never to hear from you brakes is the horrible scraping of metal on metal. In such cases, you have no brake pad left and are literally stopping your car by grinding your metal brake pad holder against your rotors or drums. After only a few instances of this metal on metal friction, you brakes parts will be absolutely ruined. As soon as you hear such metallic scraping, call a tow truck and get to a mechanic ASAP. The money you spend on the tow will be nothing compared to the money you’d spend on an entire new brake system if you keep using the car and scraping to a stop.
''' Brakes feel funny. What I mean when I say “feels funny” is when the brake pedal feels spongy or lower than normal, or when you have to step on the brakes harder to get the car to stop. Another “feels funny” is when you step on the brake pedal and the car pulls to one side. If you experience any of this when stopping your car, take it to your trusted mechanic to find out why this is happening, and what needs to be repaired.
If you have any doubts about your brakes, ask your auto technician to go for a ride with you to determine if your brakes are working properly and safely. I feel brakes should be at the top of your list of repairs never to be put off. If the car won’t start it is a great inconvenience, but if the car won’t stop, it can be deadly.
〉 Answered on Jun 2nd, 2011 by Amy Mattinat, Owner and Author at Auto Craftsmen Ltd
Brakes should be replaced when the pads are less than 2/32 of an inch.
If your brakes seem "light" or are making an unusual noise, you should get them checked. The time between replacement depends so much on driving habits, environment, the quality of the parts and the make/model of the car. Of course, your brake warning light on your dash (if equipped) will inform you when attention is needed. It's actually a good idea to have them visually inspected with every oil change.
〉 Answered on Jun 2nd, 2011 by Judy Curry, Co-Founder and Vice President of Marketing at Currys Auto Service
Brake replacement is impacted by how the vehicle is used (City/Highway/Mountain) and the type of vehicle. Some brakes have warning sensors that alert you, but the best way to know is to have the brake inspected for wear at your independent shop. Also, the brakes should be visually inspected at each tire rotation.
〉 Answered on Jun 2nd, 2011 by Julie Scroggins, Vice President, CFO at Waukegan Tire and Supply Company Inc.
Your Brakes are the only thing stopping your vehicle,so be aware of noises & changes in your brake pedal. The signal that the manufacturers put in the pad is an metal indicator, you may hear chirping or squealing. This is your warning to make an appt to have them looked at, before their is damage to anything else that would be costly! Remembering Squealing is a warning, Grinding is BAD! Here is a short video to give you more insight! http://communitytireaz.autotipsblog.com/category/brakes/
〉 Answered on Jun 2nd, 2011 by Pat Fleischmann, Director of First Impressions at Community Tire Pros & Auto Repair