If the accounts are set up properly, a husband and wife could have upwards of $800,000 fully insured at one bank, according to Barr.

Here's how it would work:

• Husband and wife each have $100,000 in an individual account.
• The couple has $200,000 in a joint account.
• Husband and wife each have $100,000 in individual retirement accounts.
• Husband and wife each set up $100,000 revocable trust accounts, payable on death, naming each other as beneficiaries.

In addition, they could set up as many revocable trusts as they want for qualified beneficiaries -- parents, siblings, spouse, children, grandchildren. Each one of those beneficiary accounts would be insured up to $100,000.

What you can see by that example is that deposits maintained in different categories of legal ownership are separately insured. The most common categories of ownership are individual, joint, and testamentary, or pay on death. Retirement accounts also are insured separately.

While you may have a living trust account, there is no ownership category called living trust. If a bank fails, the FDIC will look at a particular living trust account and decide whether it's an individual, joint or pay-on-death account.

"The average depositor isn't going to know which category the account will be in," says FDIC attorney Chris Hencke. "Some bankers take the optimistic viewpoint and assume it will be put in the "pay-on-death" category with its generous per beneficiary coverage -- as opposed to the individual ownership category where coverage is just $100,000.

"It depends on the terms of the living trust agreement. If the bank fails and they get stuck in the single category, they've put all this money in the account thinking it's covered per beneficiary when it's per owner."

Hencke says many living trusts have "defeating contingencies" with respect to the beneficiaries. A defeating contingency is a restriction that disqualifies the account from additional insurance coverage. Trusts that have defeating contingencies won't get per-beneficiary coverage.

"The pay-on-death category is designed to be simple -- you die, the money goes to a designated beneficiary. But with a living trust, it isn't usually that simple. If there's some doubt as to whether the beneficiary will ever get the money after the owner dies, it goes to single ownership," Hencke says.

For instance: "When I die, give it to my three kids but don't give it to them until they graduate from college, and if they haven't graduated by the time they're 40, give it to charity."

Sometimes the FDIC determines that an account the bank considers a joint account really isn't.

Suppose a parent opens a joint account with a child but doesn't want the child to have free access to the account while the parent is alive. The parent stipulates that the child needs the parent's signature to withdraw money.

The FDIC says all parties of a joint account must have equal access and withdrawal rights for it to truly be a joint account. If the bank fails, that account would likely be considered an individual account and insured for only $100,000 instead of $200,000.

Also, dividing your money among different branches of the same bank won't work either. The main office and all its branches are considered one bank.

Obviously, it's easy to get tripped up and make a mistake.

Read the FDIC rules online or ask your bank for a copy of the FDIC booklet, "Your Insured Deposit."

Don't stop there -- when you think you have it structured correctly, call the FDIC consumer hotline, (877) 275-3342, and check with them.

And while it's always smart to make sure deposits you have with a bank are covered by FDIC insurance, you also ought to keep tabs on the health of your bank. Bankrate.com's Safe & Sound rating feature lets you see the financial condition of banks, thrifts and credit unions. Check out your bank and make sure it's strong enough to keep your money safe and sound.