What about company policies ?

I've worked in a few large organizations, and they've all had internal policies of keeping the PC on for doing scheduled maintenance (backups and such) during the night.

I worked in one shop where I actually got in trouble for turning off the PC because it somehow borked the nightly save (what idiot designed THAT software ?) !

SO yeah, PCs are left on, but it's more for the convenience of the IT department - and by extension, that of the users who do not see an IT guy hanging around or initiating a backup manually right you need to finish that code.

I used to actively subscribe to the avoid-power-cycles theory until I got my first Athlon Thunderbird. When I noticed how much juice that baby could suck down in a week of 24/7 operation, I changed my mind and now I turn off the buggers when I know I won't be using them for more than 4 hours. Just realize that there are now 1KW PSUs on sale and I'm sure you'll agree that it is preferable to power those suckers (literal use) down.