While this is good insurance on protecting your brake system back in the late70s -80s a lot of cars never had brake fluid changes unless a brake line or part failed ! Is this more of an issue because of antilock brakes or different metal in the calipers or just because cars are lasting longer ? If you’d try to sell a brake fluid change back then they would call you a con artist , now standard procedure .but cars were a lot cheaper and were replaced more frequently !I use a syringe to draw out the dirty brake and clutch (if you have one) fluid. Don't draw out every last bit to expose the cylinder holes; that way, you may not need to bleed the system.
Dirty brake fluid can cause the car's master cylinder to begin leaking. The black particulate matter ruins the piston seals.
I change fluids once every two years.
Automotive Fluid Extractor.