Three - one to change it, one to not-change it and one to both change-and not-change it.
Just one, but they have to steal it first.
None. They wait for the electrician to make a mistake and yell at them for doing it wrong.
None. Real Men aren't afraid of the dark.
1.99904274017 but that's close enough for non-technical people.
Because they're acetic.
No Bhikkhunis(https://en.wikipedia.org/wiki/Bhikkhuni) allowed.