As the availability of credit tightens nationally, the next hit could be the limit on your credit card.

That's especially possible if you tend to carry a high balance that's close to the credit limit, pay only the minimum on your balances, make late payments or have a low-to-moderate credit rating, said consumer experts.

So, it's even more important than ever to pay off your debts, they said.

''Lenders are playing defense instead of offense,'' said Greg McBride, senior financial analyst at Bankrate.com. ''Lenders aren't going to go back to standing out on the street corners handing out cards like it's candy anymore. This is going to be an environment where riskier borrowers will have a harder time getting credit.''

Lenders are focused on limiting their risks and protecting themselves, said Bill Hardekopf, chief executive officer of Lowcards.com, an independent Web site that compares and reviews credit cards (http://www.lowcards.com).

The changes could lead to both decreases in the credit limits and increases in annual percentage rates (APRs) on credit cards, he said.

''In the terms and conditions of just about every credit card, it says that an issuer has the right to change the rate at any time for any reason as market conditions warrant,'' Hardekopf said. ''Obviously [market conditions] stink right now. The market is very rough.''

People who miss payments or go over their credit limit will usually see an interest rate increase, he said.

Hardekopf said he has not heard of any across-the-board credit-limit decreases, though McBride said there are some borrowers with good credit and low balances who might get caught up in credit-limit decisions not based on individual reviews.

Issuers by law must notify customers of the limit decrease, but Hardekopf and McBride said notices can be easy to miss.

''How many people look at every single thing that's put into their credit card statement?'' asked Hardekopf.

The notice could also come in a direct-mail piece that looks like junk mail, or if you have signed up for paperless statements, you might get an e-mail, they said.

A Stow woman who asked to remain anonymous found out about her credit card limit decrease before she ever heard from the issuer. She had signed up for automatic e-mail alerts that would tell her when she was within $200 of her credit limit.

The woman said she and her husband had been running a balance of $8,400 for appliances they charged at a department store after they sold their Hudson home for less than expected to downsize to another house. Their credit limit was $9,000.

A few weeks ago, she received an e-mail saying she was within $200 of her credit limit. She thought something was wrong, since she knew she had not been using the card.

It turns out her credit limit was reduced to $8,600 — $200 above her current balance.

She worries about the effect the reduction will have on her credit.

''It's amazing how we went from exceptional credit being able to own two homes to here they're cutting us. It's the tumbleweed effect that's the hard part,'' she said.

Experts said credit scores are typically determined by looking at the total amount of debt compared to available credit, not individual account debt ratios.

A few days later, the official notice of her credit line decrease came in a white envelope that could have easily been mistaken for junk mail, she said.

Another important reason to keep an eye on your credit limit, if you tend to run a balance close to it, is cards are not always declined at the checkout register when the balance goes above the credit limit.

''It used to be years ago, 'I'm sorry, ma'am, your card is no good.' They don't decline anything. It seems they blow by [the credit limit] and collect the over-the-limit fee, which can be $30 to $35. If you use too much of your credit limit, then you might be in line for an APR increase,'' Hardekopf said.

A few issuers have terms and conditions that subject consumers to a default rate of 28 to 30 percent if you exceed a credit limit twice within a 12-month period, Hardekopf said.

The best defense against a credit line decrease is responsible borrowing.

''It's all about limiting exposure'' for the banks, McBride said. ''Somebody who carries a $5,000 balance month after month is a lot different from someone who runs up a $5,000 balance and pays it off.''

The banks want those good customers who pay off their balances to keep buying and they're less likely to see the decrease. The banks might not make money on you in interest payments, but they're making money on the merchants who allow you to use your cards, he said.

And there's one more thing.

''They're hoping that all of a sudden, you miss a payment and it gets caught up in the stack of mail that everyone has,'' Hardekopf said.