Rule 10: Items displayed in the house have to pass a test.
This seems only fair. After all, you have only so much space. The items taking up that space should justify themselves. It's not a complicated test. They just have to have a valid reason for being there. The reason can involve function or form. No problem. It passes the test. But it doesn't pass just because someone put it there "for now" five years ago and it's never been moved since, or because someone gave it to you who might notice if it's gone, or because you don't know where else to put it.
Rule 1: When in doubt, throw it out.
Rule 2: Use it or lose it.
Rule 3: Efficiency counts, so store things accordingly.
Rule 4: Handle something once.
Rule 5: Recycle it.
Rule 6: Pick a number and stick with it.
Rule 7: Use a file cabinet.
Rule 8: Do Something.
Rule 9: A place for everything, and everything in its place.
Rule 10: Items displayed in the house have to pass a test.
Rule 11: Don't do things "later."
Rule 12: Label things.
Rule 13: Call in a professional.