Brakes are, conveniently, one of the most obvious automotive components to show wear, and drivers rarely go long between repairs once the car starts making the tell-tale squeaking or grinding noises. Even if the driver can somehow ignore the pulsation in his foot from a failing brake system, his passengers and passersby will likely remind him to “get those fixed!”
Because it’s a primary safety issue, drivers will typically agree to some recommended service procedures during a necessary brake job. Pads are usually a no-brainer. Rotor replacement may take a bit more effort. But calipers don’t always get the attention they deserve.