If you break a mirror it's seven years bad luck right?  Well if you break another mirror in that amount of time, do you get credit for the time you have left?  I mean, if you break one, and three years later, break another does that mean seven years or eleven?

Also, if you break a piece of a mirror that has already been broken, does that count as a mirror?

According to section 3A of the British Parliamentary Luck Act (1793) hereafter refered to as Murphy's Law, if you break a mirror you will receive seven years bad luck.
If through an error in processing you do not receive your seven years of bad luck the government retains the right to credit you with unlucky things at any time upto forteen years from the origional breakage.

The breaking of a mirror during a period of the bad luck is in itself an unlucky thing to happen according to the Act and therefore counts as part of the bad luck from the origional breakage and should under no circumstances be used as an excuse to get a longer period of bad luck.

This was tested in the High Court in 1800 in Crown V B'stard.

Sadly the law was repealed in 1999 and replaced by the Positive Vibes Man Act of the same year.

Will

I am not sure of the status of repealed British acts of parliament under International law.  The pieces of Mirror belong to the breaker.

A little know war was fought between Britain and Slovenia in 1831 over this very subject.  It lasted three days and was caused when the Ambassador to St James Court from Slovenia tripped and broke a mirror in London.  He was naturally sent the pieces of mirror as a receipt for his impending bad luck.  This is a deadly insult in Slovenia and things got a little nasty for a while.

Will

I'm sure the UN has all this covered in one of their charters