Two, but you have to get them in the lightbulb first.
None. It will change when the fire nation attacks
1001 1 to offer up the bulb and 1000 to scream 'Get in the hole'
Two. One to screw it in and one to film it. One, but it takes him fifty tries.
Just one to hold the bulb while the world revolves around them.
A psychologist pulls habits out of rats!
Rats!