7 On Your Side: Are new credit card bonus offers worth making the switch?

SAN FRANCISCO (KGO) -- You see the offers everywhere. Cash back and bonuses just for opening a new credit card.

If your mailbox is stuffed with credit card offers, you're not alone. Banks are sweetening the deals with sign-up bonuses.

But not everyone's biting.

"If you've got a regular credit card that doesn't reward you with two percent cash back, you can do better," explained Joe Ridout with Consumer Action.

And yet, a new survey by CreditCards.com says most cardholders are ignoring those sweet deals.

About 25 million Americans have stuck with the same cards for 10 years, many with no rewards

"Usually I think those rewards are tricks to get you to trade to another card, but then it costs you in the end," said consumer John O'Keefe.

"I'm probably missing out on a lot, but I mean you get so many of them in the mail," said another.

So, are you missing out?

"If you're just buying the things you ordinarily would buy, it's found money, or you could pick up a really nice sign-up bonus and treat yourself to a vacation," said Ridout.

Plenty of cards offer immediate cash just for signing up, or bonus points that buy you plane tickets or hotel stays. Yet millions of consumers are sticking with their old cards.

"Some people do feel a kind of loyalty to a bank, even if the bank may not be necessarily loyal to them," explained Ridout.

And there can be drawbacks to those deals.

First, many give you a bonus only after you spend a certain amount of money, such as 50,000 points but only if you spend $4,000 within three months.

"That's dangerous and it can induce someone to spend much more than they otherwise would have," said Ridout.

Overspending may cause delinquencies and penalties, wiping out the benefit of those rewards.

Remember opening new credit cards also can harm your credit rating, at least temporarily.

And you should avoid closing old accounts. Those are the ones that boost your credit rating.

Consumer Reports is published by Consumers Union. Both Consumer Reports and Consumers Union are not-for-profit organizations that accept no advertising. Neither has any commercial relationship with any advertiser or sponsor on this site.

(All Consumer Reports Material Copyright 2014. Consumers Union of U.S. Inc. ALL RIGHTS RESERVED.)