None. The light bulb shall never burn out. (OK. It's more cathartic than funny...)
I'm burning, I'm burning, I'm burning Beru.
He tried to blow up a police car.
Two. One to hold the light bulb and one to drink until the room spins.
Probably one but you can't generalise.
She doesn't, she just holds it in the socket and waits for the world to revolve around her.
If this gets 500 upvotes i'll tell you!