I made a trip to Costco to buy business supplies last week. While browsing the software, I spotted the latest version of Quicken. I picked up the box and looked at the list of new features. I felt that urge creep upon me — the urge to spend. “Maybe the Mac version is out, too,” I thought. “I should stop by Fry's to check.”

Then I thought of the $50 it would cost to upgrade. I thought how Quicken 2004 has served me well for three years. I began to have doubts. “I'll use the 30-day rule,” I told myself. “If I still want this next month, I'll buy it.”

Related >> How to Track Your Spending (and why you should)

The 30-day Rule is a Simple Method to Control Impulse Spending.

Here's how it works:

1. Whenever you feel the urge to splurge — whether it's for new shoes, a new videogame, or a new car — force yourself to stop. If you're already holding the item, put it back. Leave the store.
2. When you get home, take a piece of paper and write down the name of the item, the store where you found it, and the price. Also write down the date.
3. Now post this note someplace obvious: a calendar, the fridge, a bulletin board. (I use a text file on my computer.)
4. For the next thirty days, think whether you really want the item, but do not buy it.
5. If, at the end of a month, the urge is still there, then consider purchasing it. (But do not use credit to do so.)

That's all there is to it. But it's surprisingly effective. The 30-day rule works especially well because you aren't actually denying yourself — you're simply delaying gratification. This rule has another advantage: it gives you a chance to research the item you want to purchase. This can save you from grief.

Related >> How to Cure a Spending Hangover

For example, after returning from my Costco trip last week, I checked the reviews on Amazon. Quicken 2007 for Mac gets 1-1/2 stars! Yikes! Still, I added it to my wishlist. A month from now, if I still feel I need it, I may allow myself to buy it.

I began using the 30-day rule about two years ago. I don't always remember to follow it, but when I do, it works well. Sometimes my urge to spend is gone by the time I get home. Sometimes the urge grows stronger for a week or two, but then subsides completely. It's rare that I decide I need something after 30 days of waiting.