In seven years of running - only two breakdowns - both without any warning. First year was a brake failure. Cause: defective master cylinder. Seal broke and master cylinder could not pressurize the wheel calipers. Towed to Cummins and master cylinder was replaced. No trouble since. Second break down was just last month. Coach would not go into gear. Towed to campground. Cause was a broken throttle return spring which caused the engine to idle too fast for the Allison to engage. Manually held the throttle lever back to hold the engine RPM down and the coach went into gear. Drove home and new springs were installed. I believe that both breakdowns were, at least in part, due to age. Don't see the need to carry a spare master cylinder or extra throttle return springs. Inconvenient breakdown? Yes indeed! Sufficient cause to quit RVing? H*** no! Jim.