Two. The light bulb you remove and the light bulb you replace it with.
Just two. One to politely ask and the other to politely help.
How many did it take last year
Twelve. Three to Physically Change the Bulb, Three to Talk About How Complicated it Was and Six to Call themselves Electricians.
Because they pack light.
A: We can see no need for uninstallation and have therefore made no provision for light bulbs to be removed.
Because it's a catastrophe :-) Yeah, ok, I'll be going now. EDIT: removed explanation.
Pollution.
Only 1, she'll hold the bulb in place and wait while the world revolves around her.