I've been following a regular cleaning routine for years
I run a utility that deletes temp files etc.
Then I do an adware scan
Then a virus scan
then a registry clean utility
then a registry defrag utility
then the disc defrag function in windows
I've done it every month or 2 for years without ill effect but recently some IT friend said "are you nuts?...don't touch the registry!"
Am I'm really doing something stupid? Oh and if you want to pity this non-technical fool...go ahead. I draw the line at outright abuse and derision though.