poweroff - Power off the computer every night and hardware life

I want to know if an office computer shuold be switched off every night or not to improve its hardware life.
I know that some components like magnetic disks are degraded by reboots, but I cannot evaluate if it is worse a daily switch off or a full day unuseful activity.

Thanks

Answer

I remember reading about this in the Google Failure Trends in a Large Disk Drive Population whitepaper. Search for 'Power Cycles'.

Though it looks like this question was asked before, in various forms:

I would assume the same applies for all moving parts... you're probably better off looking at power savings though.