"Q:" How many psychiatrists does it take to change a light bulb?
"A:" Only one, but the bulb has to really WANT to change.
"A:" None, the bulb will change itself when it is ready.
"Q:" How long does it take?
"A:" For a 100 watter, about 750 hours (check package for details).
Moral: Don't hire a psychiatrist to change your light bulbs.