Is it time to trade in your old credit card?

With issuers changing interest rates, credit limits and other terms and conditions in response to the credit crunch and to new federal regulations, experts say it may be time for borrowers to reevaluate their plastic.

"So many things have been changed in the fine print that you need to catch up with what your card issuer is doing now," said Gerri Detweiler, credit advisor for Credit.com.

Card issuers have sent out notices in recent weeks, informing their customers of the often sweeping changes. Some have sent out formal notices, whereas others are implementing changes after mentioning them in statement stuffers that many consumers toss out as junk mail. If you haven't paid enough attention, Detweiler said, your cards may have become toxic without your notice.

"Whether your fees are being raised or your limits are being cut, this is a good time to see whether the cards you have are good in relation to what else is out there," said Bill Hardekopf, founder of .

But any savvy evaluation of your choices is going to hinge on your credit score and how you use your cards, Hardekopf said.

In today's dicey credit environment, you need a very good credit score to get a new card. And because applying for credit can hurt your score, you don't want to apply randomly. Indeed, several experts now suggest that consumers get their credit scores before shopping.

In some cases, their scores may reveal that they shouldn't shop at all, Detweiler said. They should instead pay off or pay down their credit cards.

"If there's not much chance that you're going to be able to get another card, you might want to get into a nonprofit credit counseling center to see if you could negotiate lower rates with your existing issuers," she said.

That's not necessarily ideal because getting a creditor to accept a negotiated rate is likely to hurt your credit score. But if your score is already too low to apply for a better deal, and if you're struggling to pay, it may be your best option.

The score most commonly used by lenders is called FICO, generated by Fair Isaac Corp. You can access your current score from MyFico.com for $16, but you can also get it free if you sign up for the 30-day free trial offer on the Web site. The downside is that it signs you up for a credit monitoring service that will cost you $90 annually. If you don't cancel within the 30-day period, the freebie turns expensive.