It’s practically impossible to live a normal life these days without credit cards.

Credit cards offer convenience, they’re safer than carrying cash, they protect your purchases and they often give you additional savings, discounts or rebates for using them. By paying your bills on time, staying well within your credit limit, you can build and maintain an excellent credit rating.

But if you’re not smart about the way you use your credit cards, they can really eat you up financially. And the government is not going to bail you out if you get in over your head.

How to Choose a Credit Card

Check out a site like CreditCards.com to search by types of credit card, by interest rate, by rewards, and by credit rating, and to compare and apply for credit card offers.

Rewards cards are great. If you’re responsible enough to pay off your balance each month, rewards credit cards will offer points, airline miles or cash back. But if you intend to carry a balance, beware: Rewards credit cards tend to have much higher interest rates than traditional credit cards.

If you intend to pay your balance in full, you should check the grace period, which is the amount of time you have to pay the balance in full before your account accrues interest charges. Grace periods are usually state in terms of days from the billing date.

If you won’t be paying the balance in full each month, look for a card that offers a low interest rate, but avoid cards with low introductory rates and higher rates after a length of time. Find out whether the interest rate is fixed or variable, and know the range of variation.

What sort of fees does the account charge? You might expect to pay annual fees, overlimit fees, and fees for paying by phone or online on your due date.

Always read the fine print, and be aware of the penalties for making late payments or missing payments. Usually, there are late fees, and your account may default to a much higher interest rate.

Use Credit Wisely

You must pay your credit card bill on time, and you must make at least the minimum payment. If you can’t manage this, don’t even apply for a credit card.

Pay your bill as soon as it arrives, since interest accumulates every day. The more quickly you submit your payment, the lower your balance will remain.

If you can afford to pay more than the minimum payment, your balance will drop more quickly, and the amount of interest you pay will also be reduced.

Transfer high-rate balances to a credit card with an interest rate, then close the higher-rate account. Choose a card to transfer balances to that offers the lowest long-term interest rate, and lowest balance-transfer fees.

Don’t use the checks the credit card company sends you. These tend to be considered a type of cash advance, which almost always incur high interest rates. Shred these or tear them up.

What’s the most important credit card lesson you’ve learned? Share your thoughts in the comments below.