My wife gets a special pleasure from this column — or, more precisely, from its name — because she has an encyclopedic memory of my bone-headed consumer mistakes. More often than not, they involved spending about $30 too much for something like a cup of coffee or a takeout lunch.

I reformed my ways years ago, but there was a time when my debit card purchases generated enough overdraft fees to count as a mini bank bailout. Even if I fall off the personal-finance wagon, that's unlikely to happen again. That's because, under new Federal Reserve rules that began to take effect this week, bank customers must opt-in to any programs allowing banks to charge overdraft fees. I don't plan on giving my bank that permission, and consumer advocacy groups say you shouldn't, either.

The Consumer Federation of America this week released a report detailing the cost of overdraft fees at 15 of the country's biggest banks. According to that research, most of the banks charged about $35 — this, despite the fact that the typical debit card purchase on an overdrawn account is only about $20. Often, the initial fee is just the beginning.

Some banks charge what are called 'sustained fees" if, after a few days, the consumer hasn't repaid the overdrawn amount plus the initial fee. In the Consumer Federation study, those fees ranged from $7 after four days to $35 after five days.

Consumer Federation figured out the price consumers pay when they overdraw by more than $10 and don't repay within 10 days. The fee amount — which doesn't include the actual overdraft itself — varied from $34 to $93.

The new Federal Reserve rules don't ban all of these overdraft fees — just those tied to ATM withdrawals and most debit card purchases. Banks can still charge customers if they overdraw their accounts by check, some electronic payments or recurring debit card charges, like automatic bill payments.

For consumers opening new accounts, the overdraft rules went into effect on Thursday. They'll be applied to existing account holders on Aug. 15.

After that, banks will need to get consumers' permission to enroll them in so-called overdraft protection programs.

Some big banks — like Bank of America and Citibank — won't offer programs allowing them to charge fees on debit card and ATM transactions. These banks simply won't allow the transactions to occur if there isn't available funds.

But many banks are rushing to enroll their customers into the programs. Critics — groups that include the Center for Responsible Lending and Consumers Union, the publisher of Consumer Reports magazine — say banks are trying to get customers to opt-in to predatory programs by exploiting their fear of public humiliation.

But consumers really do fear the embarrassment of having a card declined at a restaurant or retailer, and protecting against that is a legitimate part of these programs' appeal, said Gail Sneed, a senior vice president at Kansas City-based UMB Bank who oversees consumer banking at St. Louis-area branches.

She said there are other benefits, too.

Sneed offers the example of a late-night grocery run, just hours before a consumer's paycheck is direct-deposited. Under the old rules, the account holder might spend more than what's available in the account, but not get hit with a penalty. That's because the paycheck would be deposited before the debit-card purchase would clear, a process that can take several hours or even a couple of days.

Under the new rules, Sneed warned, banks won't allow those transactions unless the consumer has opted into an overdraft program.

Sneed said that scenario is a lot more common than most people realize. She said about half of all transactions that push accounts into a negative balance never are assessed a fee because more money is deposited before the transactions clear.

Of course, that means that the other 50 percent of the time, consumers are getting hit with fees. If you don't care about how a cashier will judge you, it's better to be declined at the point of purchase and use another form of payment, like a credit card.

Or, for consumers worried about the awkwardness of having their cards declined, most banks offer far cheaper forms of overdraft protection that tap into savings accounts, bank-issued credit cards or lines of credit to cover any shortfalls. But don't expect to get any solicitations this summer about those offerings. You probably will need to seek them out.