Drinking, bathing, washing, swimming, etc.
or
The bartender offers him a warm smile and says, "For you, no charge".
or
Jammies!
or
Three: One to screw it in, and the other two to help him down off the keg.
or
Two. One to change the bulb, and one to write a song about how good the old light bulb was.
or
Just one, but he/she will spend hours checking for technical problems.
or
Because he never pays his debts.
or