Three. One to change it while the other two argue about how old the old one is.
Who wants to know?
No one knows, they wait for it to burn out and follow it around for twenty years.
None. cmon , they'd much rather be kept in the dark.
THAT'S NOT FUNNY!
Someone whose career is in ruins.
5. 1 to screw in the light bulb, and 4 to remark on how grand the old one was.