ATLANTA -- The economy is changing the way we shop for groceries. A new study released by Atlanta firm Miller Zell showed shopping with a list is up dramatically from just a few months ago. But making a list and sticking to it are two different things.

Consumer Advisor Clark Howard shows you when it’s OK to make an impulse buy -- and when to steer clear.

When Stephanie Nelson, also known as the coupon mom, goes to the store she’s armed and dangerous.

“I don’t know if I’ve ever gone into a grocery store without a list,” said Nelson.

Last December, a survey by Atlanta marketing company Miller Zell showed 45% of people shopped for groceries with lists. The latest survey showed that 65% of us are list makers now.

“Consumers are being a lot more careful and rational about the decisions that they make in the store,” said Steven Skinner with Miller Zell.

Still, the Miller Zell survey showed people would change their mind right in the store about what to buy if an advertiser swayed them.

Clark says -- don’t let them. Keep your goal front and center.

“My goal at the end is to see how much I saved on my receipt and it shows me the percentage I saved. Well, if I throw in full-priced items I hadn’t planned on, it’s going to throw off my percentage. It kind of ruins the game,” said Nelson.

List making and coupon clipping take effort -- but is it worth it?

Stephanie’s purchase that day at the grocery store totaled more than $90. Subtract all the store specials and she’s down to $52. Then add in her healthy dose of coupons and her bottom line?

$6.62.

“So 93 percent. That’s good because we stuck to our lists,” said Nelson.

“You know, your results are going to vary based on how scientific you are about following the list, but here’s my challenge for you – I want you to beat Stephanie,” said Clark. “If you can do that, you’re going to know you’re an accomplished shopper.”

Not only are consumers being more careful in the grocery store, but they’re also cutting back on credit card debt. Borrowing dropped by the largest amount on record in July.

The Federal Reserve said consumers cut back on their credit by more than $21 billion.