Two at most.
They know people will blow them.
Because its white and it works.
They both ask for change and never get any.
1001 1 to offer up the bulb and 1000 to scream 'Get in the hole'
100. 1 to change the light bulb and the other 99 to complain about how the old light bulb was much better.
One.
Because they can't count to
Uranium gets to its half-life on time.