[johnnyrod]

There's preventative maintenance and there's wasting your time, there's also starting a job you don't know how to do. Up to you to figure out which is which and when the calipers were last rebuilt, and how they look now. Ideally you'd do everything but in the real world where a set of caliper seals is about £20 a side plus fluid and there's the question of time and space to work in, you don't always get ideal.