Americans need to start checking their cash before they cash their checks.

Debit cards, direct deposit, and Venmo are all the rage these days. But new research from the Consumer Financial Protection Bureau shows that we’re pretty bad at using these responsibly.

The data show that Americans paid a total of $15 billion in overdraft fees — which include fees for bounced checks or overdrawn accounts — in 2016. Consumers were charged an average of $34 for each incident, and frequent overdrafters end up forking over $450 in fees.

Some of that cost can be attributed to banks’ lack of transparency in overdraft policies, but experts say it also comes down to American consumers’ struggling to manage their money smartly. In fact, paying too much in overdraft fees is just one of many mistakes that Americans make when it comes to their bank accounts. Here are five:

  1. Not knowing your balance at all times. You should have your bank’s mobile app and check it frequently, says Greg McBride, the chief financial analyst at Bankrate.com. “With 24/7 online and mobile access, there’s really no excuse not to have tabs on your account balance before initiating transactions,” McBride tells Moneyish. Multiple overdraft fees in a row can cost you hundreds of dollars —so it’s worth your while to consistently make sure you’re not spending more than you have. Additionally, McBride suggests making sure your checking and your savings accounts are with the same bank and linked. That way, if you do overdraw, the money can be pulled from your savings account, and you won’t owe your bank a hefty fee.
  2. Paying service fees. There’s absolutely no reason to pay for a checking account, McBride says. If you’re paying a fee, “you need to know the requirements of the account. You may not be maintaining the balance that’s required to avoid the fee. If you’re not signed up for direct deposit, you may be incurring a fee that way.” But if there’s no way to avoid the fee, McBride advises switching to a free checking account, which are available at many credit unions, online-only and community banks.
  3. Keeping too much money in your checking account. Checking accounts often come with very low interest, or no interest at all, cautions McBride. “Treat your checking account like a gas tank,” he tells Moneyish. “You fill it up on payday, and as the bills come in during the month, the balance declines until the next payday fills it back up again.” So keep the money you need for your expenses in your checking account, but you’ll get a better return on the rest of your cash if you hoard it in your savings or another type of higher interest account.
  4. Getting too attached to one bank. People often default to using the bank their parents used, or the one located close to them, says Alison Norris, financial planner at personal finance company SoFi, but they should be shopping around for the most competitive interest rates and the fewest excessive penalties and fees. “You shop for everything else you buy,” she says, “so why not a high-yield savings account?”
  5. Blaming the bank. Many people switch banks when they find themselves constantly paying overdraft fees, says Norris, but even the bank of your dreams can’t make up for bad spending habits. It’s important to be honest with yourself about where your fees are coming from. The safest and easiest way to avoid such fees is always, according to Norris, “changing your habits, maintaining a large enough cash buffer, and…resolving to spend within your means.”