When it comes to financial products, none is so changeable and possibly confusing as credit cards. Interest rates, due dates and agreement terms can change with only a few weeks' notice to the cardholder. And if you get fed up with one card and cancel it, your credit score may be depressed. So how can cardholders make the most of their situation?

We've assembled seven good moves for cardholders to make this year in light of changes in the credit card business, new products and the economic conditions in the country. Here's what you should do in the coming year:

Switch to a card with rewards
Like the majority of cardholders, you probably still use the card you've had the longest time. A study by MasterCard revealed that nearly three-quarters of cardholders still had the same credit card 15 years after they got it in college.

Most likely that card doesn't have rewards or a cash-back component. If it does have rewards, you might be paying an annual fee to be enrolled in the program. Or it might be an airline card on which you've been piling up points for years but have never gotten a free ride.

Your best move for 2008 is to switch to a new rewards card.

Plastic surgery

• Switch to a card with rewards. • Redeem your points for rewards. • Pay off the balance. • Shop for a better interest rate. • Read the monthly statement. • Check your credit report. • Curb spending with a debit card.

"Consumers need to take a look at a card they've had for a long time," says Curtis Arnold, founder of CardRatings.com. "You can do better and avoid the hassle of redeeming miles, expiration dates, ticket fees, blackout dates."

You can compare cards online using Bankrate's search engine.

"Most consumers think it's a big hassle to do. That's not really so," Arnold says. "It's a matter of going online and applying. It takes five minutes now. You'll have the card in five to 10 business days."

Arnold says cardholders should leave the other account open for credit score reasons. And he notes that you probably shouldn't switch if you're close to reaching a goal with airline points. "Assuming you don't have a lot of points banked, it's an easy process," he says.

Before you get a card for a rewards program, be sure to check out the details and think about how you'll actually use the rewards. For example, if you only travel during the holidays, it may not pay to have an airline rewards program because often those dates are blacked out or few seats are available for rewards. And most airline cards carry an annual fee.

Last year, many of the credit card issuers, like American Express, pumped up their rewards programs to offer experiential rewards and concierge services to help cardholders book concert tickets or get a special dinner reservation.

But Arnold still thinks the best bet for rewards is cash back.

"I prefer cash-back cards for several reasons, not the least of which is simplicity. With cash-back cards, there is no need to worry about the actual value of your rebate, redeeming points for airline tickets, gift card expiration dates, choosing expensive merchandise out of a catalog, etc. I like the KISS -- Keep It Simple Stupid -- method and think the easier and simpler a reward program is, the more likely consumers are to effectively utilize the program."

If you find a rewards card from the issuer of your current card, you can ask the card issuer for a product change and it won't be considered a new credit card account, even though you'll have a new number.

Of course, if you carry a balance from month to month, the interest you're paying on the loan will eat up any cash rewards you have earned. Plus, reward cards often have higher annual percentage rates than regular cards.