If you have a checking account, you probably have a debit card. And that's OK.

It can be a good addition to your wallet if you follow our seven rules for being a smart debit card owner.

Debit cards can eliminate the cost and hassle of writing checks, be a quick source of cash 24/7, and make you a more disciplined spender.

Buy something with a credit card and you don't have to worry about the bill for weeks. Buy something with a debit card and the money can disappear from your checking account in a matter of hours.

You'll think more and spend less. Trust us.

Here's how to enjoy that convenience without a lot of nasty fees and other problems:

Rule 1. Never pay a fee to use your debit card at a store or at your bank's own ATMs.

A recent survey found seven out of 100 banks still charge transaction fees for using a debit card to make a purchase or withdraw cash at their own ATMs. If your bank is one of them, demand that those fees be dropped. If it refuses, move your checking account to another bank or credit union.

Rule 2. Limit your liability to $50 if your card is lost or stolen.

That's the most you're required to pay if a credit card is fraudulently used. You shouldn't be on the hook for a penny more if your debit card falls into the wrong hands.

Indeed, the best banks charge nothing if you report a loss or fraudulent withdrawal within 48 hours.

Nor should your bank make a bad situation worse by:

• Bouncing legitimate checks or imposing fees for being overdrawn after a crook cleans out your account.
• Taking more than a couple of days to replace any stolen money. Legally it has 10 business days to do that. But any bank that cuts you off from your money for that long doesn't deserve your business.

Rule 3. Reward programs are nice but not essential.

Fourteen of the top 15 banks that issue Visa debit cards now have a rewards program. They work a lot like your credit card reward programs, allowing you to earn cash rebates, gift cards or airline tickets.

But don't let such a perk suck you into a high-cost checking account. Your top priority should be an account that charges no monthly fees, no transaction fees and reasonable penalties if you screw up and overdraw your account.

Those kinds of charges can quickly wipe out the benefit of even the best reward program.

Rule 4. Always sign for purchases, don't use your PIN.

Just about everyone who uses a debit card has been asked the question, "Debit or credit?"

Retailers will steer you toward the pad to punch in your personal identification number or PIN because they pay much lower fees to process those transactions than when you push the "Credit" key and sign for the purchase.

But using your debit card like a credit card means your transaction goes through the Visa or MasterCard network, providing you with all the same consumer protections as a credit card.

And then there are those reward programs. Most of them only pony up the points for purchases made with a signature. PIN purchases don't count, or count for less. Check with the issuer to see how its program works.

Rule 5. Protect your PIN with your life.

The exception to Rule 4 is when you'd like cash back from a merchant or an ATM.

Then you have to use your PIN, and these four-digit numbers are the Achilles heel of debit cards.

If someone gets a hold of your card and PIN, your checking account can be drained in a hurry. Most banks will replace those funds, but it could take several days, and in the meantime, you could be bouncing checks and running up all sorts of fees.

So don't write your PIN on the back of the card or on anything else you carry in your wallet or purse. Don't pick an obvious number, such as your birthday or the last four digits of your Social Security number, driver's license or any other number that might be in your wallet or purse.

Covering keypads with your free hand while punching in your PIN makes it harder for thieves in line behind you to see it and make you their next target.

"It is very easy for someone who does not have your best interest in mind to watch what you do and use your information," says Bettye Banks, vice president for education at Consumer Credit Counseling Service of Greater Dallas. "If someone snatches your purse, they could use it very quickly."

Rule 6 Avoid ATMs that don't belong to your bank.

When you get cash from another bank's ATM it will charge you a fee and your bank will charge you a fee as well. Typical cost: $3 to $4, when you combine both fees. Do that a few times a month and you're the banker's best friend.

Never use unbranded ATM machines, especially those found in convenience stores. They have the highest fees and have been used in sophisticated scams to steal PINs and loot bank accounts.

A smarter way to get cash is to buy something small but essential at a store and ask for cash back. Most retailers will provide up to $50.

Rule 7. Don't overdraw your checking account with your debit card.

Many consumers mistakenly believe banks won't allow them to overdraw their checking accounts with a debit card.

At one time that was true. When check cards first appeared, banks would deny purchases or ATM withdrawals that exceeded the balance in your account.

Now they're happy to approve those transactions under the friendly-sounding phrase of "overdraft protection" -- and charge you a fee for insufficient funds. Your bank will also bounce any checks that show up for payment, imposing additional penalties for each of them, until you deposit enough money to get back in the black.

A study by the Center for Responsible Lending found consumers typically overdraft less with a debit card than a check -- $14.75 vs. $31 -- but incur a higher fee -- $34 for the debit card purchase vs. $31 for the check.

By Pat Curry

Interest.com Contributing Editor

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