Three: One to screw it in, and two to talk about how much better it is than with a man.
or
A crane.
or
One; after reflecting in the twilight on the merit of the previous bulb.
or
50. One to screw in the light bulb and the remaining 49 to guard him .
or
At the Whale-weigh station.
or
When a rooster wakes up in the morning, its primal urge is to cluck defiance.
or