Two: One to change it, and the other one to change it back again.
She's only happy when "It's Complicated."
It takes two. One to change the bulb and the other to kick the switch.
A: Uh...standby I'll check on that.
A: Two-one to shoot the old bulb out and one to screw the new one in.
Because deep down, they're good people.
They both have a one in 100 million chance of being human.