There is no more frustrating job than maintenance, at least as it is practiced in most of the shops I have visited. Lack of planning, surprise breakdowns, poor communication, and Murphy himself all conspire to keep tradespeople from doing the work they come in to do every day. It is common for wrench time, as a percentage of paid time, to be in the low 30 percent range at the beginning of an improvement effort. By the time the department reaches the 60 percent range, they are sneaking up on world class performance.
From 'Second Opinion'