Back in the day, I never did anything to the brakes except swap out pads when I was absolutely forced to. Do things differently now.
In addition to a total flush every 3-5 years, we also drain and fill the entire contents of the brake reservoir on our Ram Cummins once a year using the vacuum line on our brake bleeder. Literally takes less than 3 min. Both the larger containers of brake fluid and the brake reservoir on our Ram hold exactly 32 oz., so no waste. When we started doing these D&F's, I did it as long-term preventative maintenance, with no expectations it would provide any noticeable improvement in braking performance. Was pleasantly surprised to find the brakes became distinctly more firm after every D&F.