Shoppers ride escalators at Water Tower Place in Chicago in this Dec. 19, 2009, photo. During the Great Recession, people have made drastic changes in how they spent their money. They stopped treating credit cards as cash and learned to save and to wait.

Bloomington, Minn. ? Think of the Mall of America as the Colosseum of American consumerism: It has more than 500 shops, 50 eateries and its own theme park, complete with an indoor roller-coaster.

And now it, too, seems a symbol of a bygone era.

Some 40 million people still visit each year. But many are like Michelle Hoppe of New London, Minn. She drove two hours to spend just $100 at three stores — Bath & Body Works, Victoria’s Secret and a toy store.

Three years ago, she says, she would show up with a “pocketful of cash” and pop in and out of stores all over the mall. “We would just spend,” says Hoppe, 45, who works as a home health aide.

The days when shopping was a leisure activity unto itself are over, at the nation’s largest shopping center and beyond. Americans are being precise in how they shop, regardless of what they are buying. They’re visiting fewer stores, checking off their lists and walking away. They’re spending fewer minutes online when they shop. They aren’t stockpiling food or clothes.

Shoppers today visit an average of three stores during a trip to the mall, according to ShopperTrak, a Chicago research firm that tracks sales and customer counts at more than 70,000 stores. That compares with an average of five stores in 2006.

Inside stores, there’s evidence that impulse buys are on the decline. Stores are messier because people dump so much merchandise before they check out, says Paco Underhill. His company, Envirosell, studies how consumers behave in stores.

‘Surgical shopping’

It’s “surgical shopping,” says John Gerzema, a brand executive at advertising and marketing firm Young & Rubicam, and co-author of a new book about the changing ways we spend money.

The shift is greatest among low-income Americans.

You can see it during the wee hours of the morning on the first day of each month. That’s when government assistance electronically drops into debit cards of millions of Americans. So they line up to get the basics just after midnight, a scene that’s increasingly common across the country. Stores that close overnight report crowds first thing in the morning.

“I have a whole strategy. I shop for the big packs every six months,” says Pia James of Harlem, who had just received her Social Security check and was clutching a fistful of coupons she had used as she left her local Costco an hour after the store opened at 10 a.m. She was pushing a cart filled with fresh vegetables and fish as well as big packs of soap and other toiletries.

Building pressure

As Americans are increasingly selective, stores are under more pressure. One or two fewer trips per shopper per month may not seem critical, but multiply that by millions of consumers, and the impact can be devastating for the retail industry.

In the first nine months of this year, the nation added about 23 million square feet of retail space, according to CoStar Group, which tracks the data. Four years ago, that figure was nearly 149 million. About 700 shopping centers broke ground compared with more than 7,000 in 2006.

At The Shoppes at Pinnacle Hills in once-booming Rogers, Ark., which opened four years ago near the headquarters of Walmart, a third of the space is empty. And some malls haven’t even been completed, like a five-story complex outside of New York that was to be the biggest in the country.

The commercial real estate industry is likely to keep struggling in part because of more targeted shopping by Americans. J.C. Penney Co.

Digital discounts

Meanwhile, websites like Groupon are becoming more popular. Since its launch in late 2008, the site has attracted 25 million subscribers around the world. They band together to get the lowest price on an item, then pounce.

Shoppers who sign up for Groupon e-mails are pitched mainly local offers, from discounts on massages to restaurants. If enough people act to take advantage, the deal takes effect. If that quota isn’t met, no one gets the deal.

The Gap’s recent Groupon offer of $25 off a $50 purchase was a blockbuster. Gap sold 441,000 offers as part of a one-day only promotion in August, for a total of $11 million.

Mall of America reports that the average number of stores per visit at its mall is rebounding to pre-recession levels, based on its own internal study. But on a recent day, it wasn’t hard to find people making more tactical strikes.

Maria Lindblom was looking for one thing: T-shirts on sale at J. Crew, which had e-mailed her a discount. She spent the rest of her time walking the mall with her mother and baby, not to shop but for exercise.

Before the recession, Lindblom used to walk in and out of shops, scooping up $60 perfumes at Nordstrom and other department stores. Now she doesn’t want to be tempted to spend.

“I’m just being conservative,” Lindblom says. “You could always lose your job.”