Elizabeth Bitton, of Brookline, Mass., asked Martin how many credit cards she should carry, and which ones.
Martin said he's recently changed his mantra of only having one credit card to maintaing two.
Martin said your first card should be one you can get through your bank. If your card is issued through your bank, Martin said, you can monitor your checking account and credit card all in the same place online. Martin recommended using this card for most of your spending.
However, he said you should have an additional backup card to use for hotel reservations, rental cars, and other purchases, if for example, you're traveling overseas. Look for a card, Martin said, that will give you a good exchange rate and low-costs for charging travel purchases. Martin recommended American Express credit cards.
Martin added that while bank credit cards are less competitive, you can get a good card from a major bank. In addition, the rewards programs are an incentive to research.
Martin recommended a few rules for rewards programs.
1. Look for the best rewards-to-points ratio.
Martin said, "With so many programs out there, some will cost you double the points to get a certain reward, may cost $5,000 points to get a $25 gift card, others might only cost half the points."
2. Rewards programs aren't just for frequent flyer miles.
"Don't use a card that's tied just to free fly miles on one airline and that's it," Martin said. "Get a rewards program you can actually use that you can get rewards programs that add cash to your retirement savings accounts. You can enroll a card to something like Upromise where you get cash added to your child's college education savings accounts, and rewards programs for things like gift cards, as well. ... Rewards you can use is the key."
But what if you're carrying a balance on your credit card?
Martin said a rewards program card is not for you if you're carrying a balance because they come with higher interest rates.
"If you're carrying a balance...you want the lowest interest rate credit card so you can pay off that balance," Martin said. "Thirteen million Americans are still carrying a balance on their credit card from last year's holiday spending and two-thirds say they'll spend less next year, so get a low interest card - not a rewards program."
Martin added that cards with annual fees aren't worth it.
"There are so many that don't have annual fees," he said. "Choose a rewards card with no annual fee because that eats into the value of a reward."