I used to work for a company that managed systems remotely. Everything from network devices, servers, etc. The sites all manage their own workstations and internal network devices, but we took care of the Enterprise.
So... One day, while looking at my logs I notice an alert pop up for one site that indicated the network devices all went down. This site in particular is a small site that does not generally have people needing outside connectivity, but they pay to have uptime and are therefore just as important as any large site. Due to the polling process of our alert system, this means that there can be a 5 minute window of error on the alert. It could have happened anytime from the second the poll went out, to 5 minutes ago when the last poll went out. I investigate by attempting to log into the device, and am able to log in without any problems. I check the logs and see...sure enough, power failure. So, I call the site admin to make sure everything is alright, and the admin tells me...No power failure at the site. He checks the network room and finds nothing out of the ordinary. Well, this warrants further investigation just to see if there is any issue with the equipment...and because I am bored enough to check on anything at this point. So after looking at logs for the last two months, I find a very interesting fact. Power Failure tickets auto-gen at the same time each Monday and Wednesday for the last two months. Long story short, we find that the cleaning lady doesn't have a free power outlet to plug in the vacuum, so is unplugging the equipment, does her work in the small area, and then plugs the equipment back in. Since the cleaning lady has room clearance, and everyone in the building knows her, there simply was never a question when she went into the small room to clean.
Now, I know its a different kind of maintenance than the OP is discussing, but I thought I would share a funny little story for your Monday. Hope you enjoy.