GARDEN CITY, N.Y. -- Giulia Pugliese is a typical teenager. She likes to look good, and she's particular about what she wears.

But when The Associated Press followed the 15-year-old from Long Island on a recent back-to-school shopping trip with friends, she left a Nike store empty-handed -- even though Nike is one of her favourites. The reason?

"I buy on sale because it's stupid to buy a pair of shorts for $60," said Pugliese, who instead looks for the "Swoosh" logo in discount stores like Marshalls.

Teens are shopping like their parents during the back-to-school season, and that's putting a lot of pressure on retailers to change the way they market to them. Gone are the spending sprees, starting weeks before school bells ring. More teens are thrifty nowadays, a habit picked up from their recession-scarred parents.

Today's kids recycle more clothes from the previous school year, mixing and matching the old with the new for different looks. They also shop year-round for things they need so they're spending less money this time of year.

When they do buy, they're less likely to get anything that's not on sale. And the number of kids who'll reuse last year's items rose to 39 per cent from 26 per cent between 2011 and 2015, says a Deloitte LLP poll of 1,000 parents.

And when teens shop, they're spending less. Families with school-age kids, on average, are expected to spend $630.36 this year, according to a survey of 6,500 by the National Retail Federation. That's down 6 per cent from last year and results have registered declines for four out of the past seven years.

Overall, back-to-school spending this year should hit $42.5 billion, up 2.1 per cent from the previous year, according to The Retail Economist, a research firm. That's much lower than the 5 to 6 per cent average gains typically seen in a healthy economy.

Teens' behaviour is an extension of how their parents learned to shop since 2008 when retailers pushed discounts to entice people to buy during the downturn. That helped lure shoppers, but it also got them addicted to deals. The shift made it difficult for stores to make money because discounts cut into profits.

Such behaviour has cut into sales from July through September, the second biggest shopping period of the year behind the winter holidays. Sales during that period were 24.9 per cent of total sales annually last year, down from 25.8 per cent in 2003, according to The Retail Economist.

"Consumers are sending a message to retailers that says 'the back-to-school shopping season just isn't that important anymore,"' says Deloitte's Alison Paul.

The shift is changing how stores market to teens. Whereas stores' promotions would end around Labor Day, they're now extending them through September. They're also pulling together complete outfits from different brands in stores to make it easier for teens to buy looks. And they're using social media campaigns to be more easily discovered by teens.

To observe teens' new behaviour, the AP followed Pugliese; her cousin, Arianna Schaden, 14; and two friends, Isabella Cimato, 17, and Sofia Harrison, 15, at Roosevelt Field mall in Garden City, N.Y. Here are some ways teens are shopping differently, and how retailers are adjusting:

THEY'RE IN NO RUSH TO BUY

Teens aren't impatient about shopping.

Although they started shopping weeks early, the four teens plan to delay buying things they don't need immediately, like jeans, until well after school starts and the weather cools. In fact, they're planning to spend about half of their back-to-school budget of about $400 after school begins.

Cimato didn't buy anything at all that day. Harrison, who bought just a few shirts, said: "To be honest, it's not that big of a deal because I shop year round."

Besides that, they want big discounts. During their shopping trip, Schaden found a $58 romper she liked, but decided to leave the mall without it.

"I think I buy on sale because my mom never buys something unless it's on sale," she said.

In response to this new thinking, Macy's and J.C. Penney are now staggering back-to-school promotions through September. Penney also is increasing the back-to-school merchandise it carries in late August and September. That includes denim, backpacks, and basics such as underwear.

And Hollister, a division of Abercrombie & Fitch, says it is timing deals on items that shoppers most want at that time. Right now, it's promoting trendy tops and T-shirts with graphics, for instance.

THEY'RE SMARTER CONSUMERS

Teens aren't roaming around at the mall for kicks during back-to-school. They're researching the looks they want online and follow popular hashtags on social media so they can piece together looks before they get there. Google says its image searches for "school outfit" have grown dramatically during the past three years, and soared 76 per cent in July.

Cimato, who researched denim tops and items with fringe on Instagram, said: "I pretty much know what I am looking for."

That presents challenges for retailers that are afraid teens will bypass their stores because they're focused on items they already want to buy. So, retailers are trying to get teens' attention before they are in stores.

Macy's is identifying key trends and hashtags on social media that are getting lots of followers. It now highlights shoe trends using the popular hashtag FWIS, which means "from where I stand."

The retailer also is putting together more looks from various labels to create outfits and displaying them on mannequins or tables in the teen department instead of showing them by merchandise category. These include looks teens haven't necessarily seen on social media.

Penney uses Pinterest personalities like Katherine Accettura and Mai Phung who are influential among teens to market its back-to-school fashions. The company says it sees up to 500 times more re-pins than if it promoted the product itself.

THEY WANT A UNIQUE LOOK

Teens no longer want to be carbon copies of each other. Now, kids, inspired by what they see on Instagram and the like, want to personalize hot looks.

"I'm not a big fan of logos," Harrison said. "That's distracting to my style."

That behaviour makes it hard for retailers to dictate specific looks. That means retailers have to do more marketing to attract teens.

Penney's back-to-school ad campaign called "Bend the Trend" tries to show how easy it is to put together trends for a personalized style. And like many teen retailers, Hollister has scaled back its logoed merchandise.

"Today, the customer is the centre of everything we do," said Hollister president Fran Horowitz.