1. Understand the consequences of “opting out” of the rate increase.

Under the law, if you opt out of the changes in terms and close the card, the card company can require you to pay off the balance in five years, or they can double the previous minimum monthly payment. If you can’t handle those consequences, be prepared to roll the debt over to another card — just watch out for balance-transfer fees. Also understand that if you close the card, it may affect your credit score because it reduces the overall amount of credit you have available.

2. Know the four conditions that will cause an interest-rate hike on your existing balance.

They’re pretty simple. The card company can boost the rate with no advance notice if: a) you have a variable interest rate tied to an index and the index rises; b) you opened the card with a teaser rate and it expires (which would be stated in your original agreement); c) you’re in a workout agreement and you haven’t made your payments as agreed; and d) you’re more than 60 days late with a payment. (Late payers can earn back their previous rate if they make minimum payments on time for six months.) You won’t get 45 days notice on any of these provisions.

3. Pay more than the minimum — especially if you have a card with balances at different rates.
Let’s say you opened a card that offered zero percent interest for six months, and continued charging on the card after the teaser expired and the rate rose to 14 percent. If you only make the minimum payment, the card company can apply that amount to the zero percent portion of your balance — while the portion at 14 percent continues to snowball. The law does require that any amount you pay over the minimum be applied to the balance with the highest annual percentage rate.

4. Pay attention to the new box that shows how long it will take to pay off your debt if you only make the minimum payment — it may shock you into action.

The CARD Act requires issuers to display that pay-off information on your bill. In 2009, nearly one in three Americans reported that they had only paid the minimum on their credit card bill sometime in the previous 12 months, according to a report by the FINRA Investor Education Foundation. The figure was 41 percent among cardholders age 18 to 29.

“A lot of people think the math is wrong. They don’t realize it will take two decades to pay (the balance) off if they only pay the minimum,” says Ulzheimer. “That box was a clear win out of the CARD Act.”

5. If you push the limit, be prepared for rejection.

The new law bans card companies from assessing a fee for going over your credit limit unless you specifically opt-in; if you don’t, the card will be rejected by the vendor. If you’re someone who uses a personal card for business, the opt-in may be worth the fee. “We’ve actually surveyed on this, and apparently embarrassment has a price,” says Ulzheimer. About half of consumers “do not want to have the waiter come back to the table and say, ‘I’m sorry your card has been declined.’”

Finally, read every notice that comes in the mail from your card company, even if it looks like junk. Girardo says Capital One sent standalone letters stamped “notification of important changes to your account.”

“We made every attempt to be transparent with customers,” she says. “It doesn’t do any good to surprise people with this.”