There's really no sure way to know.
They all left.
I DON'T KNOW I DON'T HAVE 4 YEAR VISION!!!!!!!!!!
None, that's what interns are for.
Three. One to change it while the other two argue about how old the old one is.
Only one but they'll insist on going through about 5 bulbs before they find one that suits this particular room and situation.
One.
Someone who stays up all night wondering whether or not there is dog.
Someone who stays up all night wondering whether or not there is a dog