It's not fair to change the number willy-nilly. Pick a number for other things around the house that contribute to overall clutter. For example, decide to keep two week's worth of Newsweek or Time . Each week, throw away the issue that's three weeks old when the new one arrives. If you have a passion for purchasing, this rule is for you.
Purses are prime examples.
Once again, pick a sensible number of purses to keep, and stick with it. If you decide on seven, this means that other purses are clutter. Rank your top seven purses, give the others to charity, and don't buy a new one until you're willing to let one go. Use this rule with shoes, socks, porcelain frogs, mustards in the fridge, or packages of paper towels in the cupboard. Also work clothes.