Woman writing in check book © Bruce Laurance\Digital Vision\Getty Images

Every bank has a slew of fees associated with opening and maintaining accounts, and those fees are on the rise. A recent study by Bankrate.com found that only 39% of noninterest checking accounts are free of a monthly charge. That's down from 45% in 2011 and 76% in 2009. Meanwhile, the average monthly service fee has jumped 25% in the past year.

But some of the biggest fees are avoidable. The following are four of the most expensive mistakes you can make with your bank accounts.

Using overdraft protection

At most banks, you can choose to allow your account to have a negative balance in order to allow a purchase to clear. For example, you have $100 in your account and forget that your car insurance payment -- which is larger than that -- is deducted automatically.

It can save you some inconvenience, but banks charge dearly for the service: The average overdraft fee is $31.26, and many banks charge upward of $35 per overdraft. The good news is that federal consumer protection law now requires you to opt in to this service.

If you have done so, you're in dangerous territory. An overdraft fee adds to your negative balance and can cause every additional transaction posted -- even for very low dollar amounts -- to trigger further overdraft fees. This can propel you deep into negative balance territory fast. Always monitor your account closely to ensure that the funds are there to cover your transactions. Or better yet, ditch the overdraft protection.

Not maintaining the minimum balance

According to the Bankrate.com survey, the average balance to avoid the fee for noninterest checking accounts is $723. That's higher than the previous year by 23%. Still, many banks reduce or even eliminate monthly maintenance and other fees if you keep a certain amount in your account at all times. This fee break often can outweigh any interest you receive in a savings account.

Writing postdated checks

Postdating a check to a future date indicates your desire for the recipient to wait until that date to present the check to the bank. However, banks legally are allowed to honor checks whenever they're presented, regardless of the date.

If the recipient is not someone you trust, it is safer to hold on to the check until there are sufficient funds in your account to cover it. The convenience of providing postdated checks is outweighed by the risk to overdrawing your account.

Using other banks' ATMs

Almost all banks charge a fee when users who are not customers use their ATMs, on average $2.50 per transaction. Some also charge a fee when their own customers use another bank's ATM. The average cost for customers using another ATM is $1.57.

How do you avoid those charges? Some banks will refund other institutions' transaction fees, so look for accounts with this feature. But the easiest way to avoid all these fees is to plan your cash flow more closely so that you can withdraw money only from your bank's ATMs.

The bottom line

The biggest mistake of all is not being aware of the consequences of your banking habits. Know your bank's policies and fees, monitor your accounts actively, and be on the lookout for lower-fee accounts.

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