The general recommendation is to change the brake fluid every 2 years. I recently purchased a motive power bleeder that has a small tank and attaches to the master cylinder. You put a different color brake fluid in the tank and pump it up like a garden sprayer. You then start at the passenger side rear (farthest from the master cylinder) and open up the bleed screw. When you see the new color brake fluid coming out of the bleed screw you close it and move to the driver's side rear brake, then the passenger side front, and finally the driver's side front. It takes about 30 minutes and is super easy to do. I usually use Super Blue Racing Brake fluid and then the Amber color of the same brand the next time. Or....you just have somebody else do it. This is an easy DIY though.