Our plant supervisor would allow only routine daily maintainence on the letter sorting machines in the post office that I worked in. Weekly and monthly was out. It took too much time and cost too much in personnel; he would have had to hire four more techs.
His rule was to run it until it broke and then fix it.
So int he middle of a run, a belt would break or a bearing (that had been squealing for days) would freeze up and the machine would be out of action until the problem could be fixed.
Sometimes it took five minutes and sometimes two days.
In the meantime he would be running around screaming (sometimes literally) about the time it was taking and the ineffeciency of the maintenance crew and the amount of overtime it was costing.
We always notified the maintainence people about potential problems and they always logged them in so we were all covered but the situation is still the same as when I left over a year and a half ago.

troll