Some credit mistakes aren’t so obvious. What’s worse, the biggest credit mistake — the one most people don’t even know they’re making — actually happens when people are trying to turn their credit score around.

I’m Adam Levin and this is the Wall Street Journal credit minute.

Closing a credit card account may seem like the best way to celebrate paying off a big, old debt, but consider this:

Every credit card represents a component of your available credit and each time you close a credit card, you are reducing the pool of available credit.

The less available credit you have, the greater percentage you’re using whenever you charge something in another account.

Exceed 10% and your credit score is likely to be negatively impacted. So when you pay off an account, feel free to cut up the card, but think twice before you close the account.

Using that card to pay a small, monthly bill can keep the account open and building good credit with little effort on your part.

I’m Adam Levin. Come visit us at Credit.com and learn how to take control of your credit.