Sometimes a little encouragement goes a long way. An Urban Institute study found that simple rules of thumb about credit card use can be an effective and inexpensive way to help people make better financial decisions.

The Urban Institute teamed up with Arizona Federal Credit Union to deliver through email, online web banners when credit card users logged in, and as calendar magnets mailed to their addresses two simple messages to influence behavior: “Don’t swipe the small stuff. Use cash when it’s under $20” and “Credit keeps charging. It adds approximately 20 percent to the total.”

advertisement | advertise on newsday

What results did they get? The “don’t swipe the small stuff” message proved to be most effective. Those who received that message, on average, had $104 less in revolving debt six months later and their balances were 2 percent lower than their baseline average.

This strategy has much potential elsewhere in money management. Says Michael Eckstein, a tax accountant in Huntington, “Between emergency funds, retirement accounts, and down payments for houses, there’s a lot worth saving for. A simple reminder to save a few extra dollars a month would go a long way.”