I have always been a firm believer in NOT shutting down my PCs. I only do restarts every few days to a week.
The other day I moved my 2nd PC and snagged the Monitor cable. The adapter broke so I shut the whole system down for two days until I picked up a new adapter. I tried to fire it up and it seems the PSU crapped the bed after the two day shutdown.
Should have known better. With PSUs and Case fans it seems as long as they stay running they are fine. I never had any crap out as long as the machine was running, not even on a reboot. I only after being turned off.