Because he saw the salad dressing!
or
The wedding wasn't much, but the reception was incredible!
or
Seven. One to change it and the other six to sing about how good the old one was.
or
Neither, they all burn shorter.
or
Two. One to change the bulb, and one to write a song about how good the old light bulb was.
or
They are both rolling in the dough!
or