How long do brake pads last and how do I know they need changing?
Anywhere between 20,000 and 70,000 miles, which is a range wide enough to be almost useless as a guide — so the signs matter far more than the mileage.
The spread is real because brake wear is dominated by how you drive rather than how far. Stop-start city driving wears pads several times faster than steady motorway miles. Heavy vehicles, towing, hilly terrain and a habit of braking late all shorten pad life substantially. Front pads typically wear two to three times faster than rear ones, because weight transfers forward under braking and the front brakes do most of the work.
The clearest warning is deliberate. Most pads include a small metal wear indicator that begins to contact the disc as the friction material thins, producing a high-pitched squeal that appears when braking and often disappears when you press harder. That noise means the pads are near the end of their usable life, not that they have failed.
A harsh grinding sound is different and more serious: it usually means the friction material is gone and metal is contacting the disc, which damages the disc as well as the pad and turns a modest job into an expensive one.
Other signs worth acting on are a brake pedal that travels further than it used to, the car pulling to one side under braking, or noticeably longer stopping distances.
You can often inspect pads visually through the wheel spokes. Most start around 10–12mm of friction material and should be replaced by about 3mm.
A slowly falling brake fluid level is normal as pads wear — a rapidly falling one is not, and means a leak.