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Credit cards can be great tools for earning money back on purchases, scoring merchant discounts and qualifying for added benefits in many product categories. But plastic lovers must always remember to tread carefully.

When leveraged incorrectly, some spending strategies can easily work against you and your wallet. The trouble starts when you stop looking at the big picture.

"Strategies go off the rails or fail when people only look at the short-term benefits," says Bruce McClary, a spokesman for ClearPoint Credit Counseling Solutions in Richmond, Va. "You need to look out on the horizon to determine if it is truly worth it."

You also need to ignore flashy marketing campaigns and focus instead on the fine print.

"Reading the terms and conditions is key," so you adequately understand the payment method you are using, says Laura Creamer, a financial education specialist with nonprofit credit counseling organization CredAbility in Atlanta.

To spare you some missteps, here are four credit card strategies that can easily work against you, as well as tips on how to keep them from backfiring:

Opening a card just to get a sign-up bonus

Sky-high sign-up bonuses have become a popular way for issuers to woo new cardholders. But many consumers don't realize these bonuses are often attached to spending thresholds, McClary says. This means you'll earn the bonus points, miles or cash back only after ringing up a target amount of purchases on your credit card.

For example, one card company is running a promotion on a card that awards cardholders 25,000 bonus points after the first purchase. Others require much larger purchases to obtain bonus points.

"A lot of credit card companies are making rewards harder to get," Creamer says.

McClary says you don't want to alter your spending habits to chase rewards points. If a bonus requires $3,000 in charges within the first three months of opening an account and you normally wouldn't spend that much, forgo the bonus points, he advises.

Fee avoidance can cost you

Big sign-up bonuses are often attached to credit cards with higher annual fees. As an added incentive to get you to apply, issuers typically waive these fees for the first year. But it's not a good idea to try to game the system by opening the account just to get the bonus, then closing it before the annual fee cycle starts. This strategy can actually damage to your credit scores.

"You're affecting the length of your credit history," so an account that's been open fewer than 12 months will drive down the average age of all the credit lines on your credit report. That average age is one of the components of your credit scores, CredAbility's Creamer says. Your scores suffer another way, too; every credit card application generates a credit inquiry, and these can cost you three to five points each.

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There's also no guarantee you'll ultimately avoid the charge. If the annual fee is imposed before you remember to close the account, you will have to pay it.

To avoid any undue damage to your credit scores, opt for a credit card only if the annual fee is in your price range. If you do aim too high or mistakenly incur an exorbitant charge, Creamer suggests that you ask your issuer to waive the fee in exchange for keeping the card open longer.

"Oftentimes, they will, especially if you've had a decent history with them," she says.

Bouncing balances from one card to another

Balance transfer offers, which allow consumers to move existing balances onto a new credit card at a low or 0% introductory annual percentage rate, can certainly be helpful to someone looking to pay down debt. However, McClary says consumers need to make sure they understand an offer's terms and conditions. 

"There's a ticking clock that starts once you make the transfer," he says, explaining that many offers feature retroactive interest on any balances you fail to pay down in the offer period. "All that interest is going to be heaped on there."

If that happens, a cardholder may be tempted to bounce the balance onto another credit card with an attractive introductory APR. Doing so repeatedly can generate a high number of credit card inquiries, which can negatively impact your scores. Such activity can also provide a debt-ridden consumer with a false sense of financial security.

"Don't fool yourself into thinking you've done something to pay (the debt) off," Creamer says. Instead, pick one card for your debt, and focus on your budget on making sure you pay off the balance in the introductory period.

Opening a store card to get a discount

Retailers have long offered big discounts if a customer opts to sign up at the register for that store's credit card. Taking up a clerk on this offer can leave you with a heavy liability, though.

"These cards have very high interest rates," Creamer says. If you carry a balance, a high rate will easily negate any deal you may have been given. Store cards typically also feature very low credit limits and can be used only at that particular retail chain. The limitations don't justify the ding to your scores from a credit inquiry.

Creamer says it's a good idea to skip the store credit card and opt instead for a more-traditional product that provides more-flexible spending and is more likely to bolster your scores.

If you do frequently shop at a particular retailer, ClearPoint's McClary suggests asking if the store offers a co-branded card backed by a traditional issuer or bank. These often feature more favorable terms and conditions and are accepted more widely.

For instance, one Amazon.com co-branded credit card works as a normal card but comes with a 13.24% APR, charges no annual fee and lets cardholders earn three points per dollar spent on purchases from the online retailer.

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