Here's what happens when you keep a credit card open for over 10 years

As you can guess, nothing dramatic happens when you reach the 10-year mark of owning a credit card. Your issuer isn't going to throw you a party (although maybe they should).

But the truth is that quietly -- maybe even without you noticing -- that old card has been adding real value. And closing it could cost you more than you'd think.

Here's what actually happens when you hold a card for a decade or more.

Your credit score gets a real boost

A good credit score is about more than making on-time payments. "Length of credit history" makes up 15% of your FICO® Score, and it factors in both your average account age and the age of your oldest account. That means the longer a card stays open, the better you look on both fronts.

Another piece of the puzzle is credit utilization, which is an even bigger deal -- it falls under "amounts owed," which accounts for 30% of your FICO® Score.

Every open card contributes to your total available credit. Close one, and your utilization ratio goes up. That's not great, especially if you carry a balance on other cards.

Already we've got two valid reasons for keeping a card open long term.

You gain leverage with your issuer

A decade or more of on-time payments is a track record issuers will take pretty seriously. If you've been a reliable borrower, that history means more leverage when you ask for a few things: a higher credit limit, better terms, a lower annual fee.

It also makes you a stronger candidate if you want to upgrade to a better card -- say, moving from a no-annual-fee cash back card to a premium travel rewards card. And you won't even have to open a new account, or lose your account history, to do it.

A no-annual-fee card becomes a quiet asset

For all the aforementioned reasons, if your old card doesn't charge an annual fee, there's very little downside to keeping it open.

You don't have to use it often, either. One small purchase every few months -- a pack of gum, for example -- is enough to keep the account active. Just make sure you don't forget to pay that tiny balance to avoid late payments.

This is one of the reasons I keep a handful of no-annual-fee cards -- they're extremely easy to justify keeping year after year.

What to do if the card has an annual fee

This is where things get more complicated. Paying $95 a year -- or $395, or $895 -- for a card that's collecting dust isn't worth it. Run some numbers on how much you're actually saving with the card each year. If that number doesn't cover the annual fee, it's probably time to move on.

But closing the card outright isn't your only move. Many issuers will let you downgrade to a less expensive card, meaning you can keep your account history intact while saving on annual fees. At the very least it's worth a quick call to your issuer so you can assess all your options.

The bottom line: A card you've had for 10-plus years is one of the more underrated assets in your wallet. If the annual fee is manageable -- or nonexistent -- I'd keep it open.

And if you're looking for a card worth holding onto for good, our list of the best no-annual-fee credit cards is a great place to start.

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