I bleed and replace my brake fluid every three years. For ATF, PS fluid and Coolant I've been doing a quick drain and fill.

I know draining and filling leaves much of the old fluid in the system, but it's just so easy to do a drain and fill when I'm set up to do other routine maintenance. With brakes, I'm concerned about flushing out the old fluid that's been sitting in the calipers. With the transmission, power steering and coolant, I figure the pump mixes up the old and new fluid pretty quickly. I have a vacuum fluid extractor that I use to thoroughly bleed the brake system, but for the power steering, it takes a couple of extra minutes to use the extractor to empty the reservoir and fill it back up with about 10oz of fresh fluid when I do the brakes. After 13 years the fluid that comes out looks clean and the pump is quiet with no leaks. For the coolant, I open the radiator drain cock and extract the coolant out of the overflow tank and then refill at the same time. Much quicker than a flush. I also drain and fill the automatic transmission in my wife's Acura every fourth oil change. The fluid always looks clean and pink and it's easy to do once I have the underbody shield off for the oil change.