Having one or two lenders cut back your credit lines can trigger a domino effect.
A good chunk of a person's credit score relates to how much outstanding debt they have as a ratio of their available credit. Someone who has $25,000 in credit card debt and another $25,000 in unused credit has a debt ratio of 50 percent. If the available pool of credit shrinks to $30,000, that ratio rises to more than 80 percent, which is considered too high.
Maybe you've read that you should keep a line of credit open even if you don't really use a particular credit card. Don't be surprised if the card issuers politely inform you that your inactive account is now closed, as they look for ways to cut their exposure. Since the card companies aren't making any money off you, it's an easy call.
To avoid this, start using those cards for occasional purchases instead of piling everything on one.
"Buy some groceries or gas and pay them off on time so you have a backup," recommended Detweiler.
When it comes to home equity lines of credit, it's not as easy to hold on to what you have.
Many banks lent 100 percent or more of a home's value and now are reining in those loans by reducing outstanding lines of credit. They also may be recalculating your home's value, and it may be lower than when you took out the loan.
If you disagree with a lender's new valuation of your home, you can appeal, but that involves paying for a new appraisal out of your pocket, with no assurance that you will get the number you were hoping for.
One thing for certain: You shouldn't count on home equity lines to pay for fixed expenses such as college tuition because they may not be there when you need them, credit experts say.
EXPERTS: WATCH BALANCES, CHECK SCORE