The only time you MUST bleed the brakes is if you suspect air in the lines, usually via caliper replacement or hose replacement. Maintenance wise I would say at least once ever 2 years. Brake fluid moisture absorbtion is primarily based on time. So if you just did the whole system, then you are good. If you only did the rears you should do the whole system again including the clutch!
-Andy
Edit: sorry it's late! LOL!
Last edited by Andy W.; 04/11/03 04:22 AM.