In industrial maintenance, an important axiom is: "every time you walk up to a working machine and do maintenance to it, there's a chance even a great technician will break it". Therefore in order to achieve the greatest reliability in your equipment you must strive to find the right balance so you're spending the best dollars and spending the best time to deal with potential problems without introducing more problems as a result.

This concept came about on the Boeing 747 project because they needed to get higher reliability and it turned out that aircraft maintenance was dramatically over maintaining aircraft and causing more equipment failures. Today aircraft have orders of magnitude better reliability because they're doing the right maintenance instead of just more.

It seems to me that medicine is about 60 years behind the curve in this regard. We think more treatment is better, even if nothing is ostensibly wrong.