In the past, some brake authorities said that flushing and refilling the system with fresh fluid wasn't worth the effort because you can't get all the old stuff out unless you disassemble the calipers and cylinders. True, you won't be able to eliminate every drop of the contaminated liquid, but you can get most of it, and that will effectively reduce the amount of moisture in the circuits. Besides water, there's that nasty sediment, which is a combination of rust and the ashy residue of burned glycol. This has always been sensible maintenance, but now the presence of expensive and intricate ABS hardware is further justification for the practice. Many of these systems are vented to the atmosphere, and there's also contamination from under-hood vapors in some layouts.
Fluid changes are cheap insurance against big-bucks repairs.
Yet, that's one of the less expensive types out there. Depending on whom you talk to, recommended intervals range from one to three years. It's our opinion that annual changes are ideal, but that you shouldn't go over twice that in any case. Peppin knows how. Now, we have one of those Snap-on brake fluid testers, and we test fluid on every car.