Money tip

? Effective Dec. 31, Delta Airlines has stipulated that customers’ SkyMiles points expire after two years rather than three years. And beginning Jan. 31, U.S. Airways Dividend Miles will expire after 18 months rather than the previous dormancy requirement of three years.

If you have U.S. Airways miles stored up but haven’t had any activity in the program for 18 months before Jan. 31, consider booking a last-minute getaway or lose all your miles.

The other major airlines in the United States – American, Continental, Northwest and United – haven’t changed their policies this year.

If you have U.S. Airways miles that will vanish come Jan. 31, don’t despair. Own a U.S. Airways Dividend Miles credit card? Use it. Any purchase will count as activity, and you won’t lose the miles. Or download a song from iTunes for just 99 cents – just go through the U.S. Airways Web site. Another option: buy something from the U.S. Airways shopping mall.

Also, consider making a minimum donation of 1,000 miles to a charity.