Service and Maintenance

Having a 13 yr old car with 260k miles, I try to do as much "preventive maintenance" whenever I have some major work done. (Shooting for a half million miles)

For example, needed to remove dash to replace climate control air-motors, so replaced AC evap drain hose and other rubber items, as well as all dash lights. However, my tech did not replace dash light rheostat, which failed about 6 months later.

Another example - ignition switch should be replaced by 200k miles, particularly if you (or previous owner) had a heavy key ring.

Any ideas on posting "lessons learned", particularly for high mileage vehicles? That way, we can benefit from others (sometimes painful) experiences?