Tips on how to avoid common mistakes when picking a credit-card rewards program

LOS ANGELES (KABC) -- We're bombarded by new credit-card offers all the time.

Like, do you want to save 10% by opening a store card?

Or how about a credit card you're already pre-approved for?

So which cards are actually worth the credit hit?

7 On Your Side brings you reward-program mistakes you should avoid.

First up on the list: Store loyalty cards.

"Generally speaking, we would advise against those rewards cards," says Nick Ewen, director of content with The Points Guy.

"They tend to be very specific, very niche. Obviously, if you are a diehard shopper, one of these locations where you're going every week or every couple of weeks, you're spending a whole lot, and you really do value those rewards, those discounts that you get - of course, feel free to do it."

Before opening a store card, examine how often you shop there, and how those benefits compare to your everyday card.

You should also check your existing credit account for rotating offers a couple times a week.

There may be special cashback deals or other discounts from stores you already planned to shop at, all without opening a new card.

Moving from the cash register to your mailbox - don't get reeled in by flashy signup bonuses for new credit cards. Also, be sure to read the fine print.

"Make sure that the card - the initial offer, as well as the ongoing benefits, including the bonus spending, the earning rates you have on your spending - aligns with the type of purchases that you're making and the type of rewards that you want to earn," Ewen says.

Adding more cards to your wallet can temporarily drop your credit score by 5 to 10 points.

That can lead to higher rates on a new car loan or mortgage.

However, you don't need to limit yourself to just one card.

If you're not considering a new loan, having more accounts can help your credit in the long run.

The more accounts with a perfect payment history, the better your credit score.

Just make sure you're not applying for too many at a time, and you're only spending within your means.