It's hard to know if you have been robbed if you're not even sure what you own.

In effect that's what's happening to some people who don't check their credit score and report regularly or even at all. If you don't check your credit it's possible that you could have been a victim of fraud or even something less villainous like a simple mistake.

If you are familiar with your credit score and your credit report, then you can see when it makes a big move and catch any fraud or errors before they impact your life. Not checking is like having a closet full of valuables that you never inventory, check, or otherwise keep track of.

Despite the clear benefits of knowing your credit score (which go well beyond just knowing when something nefarious has happened) 50% of Americans have not checked their credit score since the Equifax (NYSE:EFX) credit card data breach occurred in 2017, according to a new report. In addition, 18% of U.S. adults have never checked their credit report or score.

A person holds a tablet showing a credit score of 811.

Checking your credit score is easy and important. Image source: Getty Images.

Why does this matter?

In early September it became public that Equifax had suffered a security breach. This exposed the personal information of 145 million consumers. That information could be used to open credit card accounts, file false tax returns, or cause other financial damage.

Of course, checking your credit report regularly is a good idea even without a major breach. Knowing where your credit stands gives you an idea as to whether you will qualify for loans and if there are areas you should be working on improving.

Having a higher credit score gives consumers easier access to credit of all types at better rates. Some employers and landlords use credit scores as well as part of their overall method of judging character.

Who isn't checking?

Of the group that has not checked their report since the breach, nearly 3 of 20 admit that they had heard "a lot" about the breach.

"Frankly, that's disturbing," said Senior Industry Analyst Matt Schulz. "If this breach won't get people to act, what will?"

Millennials, at least those who heard about the Equifax breach, were more likely than any other age group to have checked their credit score and report in the last six months (34%). Older Millennials, those ages 31-37, were even better, with 45% having checked both. No other age segment topped 35%.

"Millennials who heard anything at all about the breach were much more likely to do exactly what they needed to do, checking their credit score and report," Schulz said. "Americans need to talk about identity theft more because it's incredibly important. If your friends and family don't know about the Equifax breach, tell them. If they've never checked their credit score or report, show them how to do it."

People are concerned

Despite the fact that 50% of U.S. adults have not checked their credit since the Equifax breach, over 7 in 10 (73%) said they are either "very" or "somewhat" concerned about the breach. Only 8% are "not at all" worried. In addition, 74% said they believe that having their personal data stolen would be worse than having their cellphone stolen, which Schultz agrees with.

"Data security is a big deal. It's not the most fun thing to talk about at the dinner table or at the water cooler, but these discussions need to be had because this problem affects virtually every American and isn't going to go away," he said.

Think of checking your credit like going to the dentist: Nobody wants to do it, but the potential damage caused by not going (or not checking) makes it worth your time.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.