BALTIMORE » Five-year-old Cayden Richey had one criterion for his new back-to-school shoes: They had to be fast.

Shopping last week with his college-age sister at Famous Footwear in suburban Baltimore, the soon-to-be kindergartner slipped on a pair of Skechers, dashed down an aisle and was sold.

Around a corner, Nora Wach, 7, remained undecided in her search for just the right shoes: probably flats, but maybe sneakers.

“Every year before school, I get her a pair of shoes,” and the third-grader can be particular, said Karen Ceanfaglione, Nora’s grandmother.

As the back-to-school shopping season ramps up, it’s not surprising that the tastes of even the youngest pupils play into purchases for school. According to the National Retail Federation, a growing number of parents say their children influence as much as half of their purchases.

“Children probably have far more sway than parents want to admit to in their purchasing decisions,” said Ken Perkins, a research analyst with Retail Metrics. “But … everybody has a budget. And at the end of the day, what you’re going to buy is going to have to fit into that.”

As retail sales have slowed this summer, retailers are counting on a boost from back-to-school shopping, a category that has seen a 42 percent jump in spending over the past decade, the retail group said. The season starts as early as July and stretches through Labor Day.

Coupled with tax-free holidays that crop up in many states this month, the period has become the second-biggest time of year for many stores after the holidays.

During the back-to-school period, “tax-free holidays are second only to Black Friday,” said Scott Markley, a spokesman for Wal-Mart.

This year, the nation’s largest retailer has rolled out a new line of Casemate school supplies and expects its children’s movie-themed backpacks, lunchboxes and notebooks, adorned with characters from “Minions,” “Frozen,” “The Avengers” and “Jurassic World,” to be popular sellers.

The National Retail Federation’s school spending survey, released last month, showed that parents expect to trim their spending this year. The average family with children in grades K-12 plans to spend $630 on electronics, apparel and other school needs, down from $669 last year, according to the survey, conducted for the NRF by Prosper Insights & Analytics. Total spending is expected to reach $24.9 billion.

And much of that spending will be driven by students’ choices.

The NRF’s survey shows that more than three-quarters of parents say children have a direct influence on up to 50 percent of their purchases. That’s up from about 72 percent of parents who answered that way two years ago.

Another survey, by the market research firm Mintel, found that one-third of back-to-school shoppers said children have a strong influence on items they purchase and nearly 40 percent of parents said they end up spending more on products for their children than when they are shopping for themselves.

Eighty-four percent of parents with children ages 6 through 11 said they sometimes or often ask their kids for their opinion when buying clothing for them, Mintel’s survey said.

At Wee Chic Boutique in suburban Baltimore, owner Bridget Quinn Stickline has filled the shop with apparel that is attractive to young customers — graphic T-shirts, vests and Under Armour athletic pants, shorts and jackets.

“Clothing is self-expression,” Stickline said. “Even if kids can’t explain that to you, they relate to certain colors and certain prints, and if you hold up a T-shirt, they’ll pick one.”

Once children get spending money of their own, they become more likely to spend to prepare for a new school year. Roughly 1 in 5 preteens is expected to spend his or her own money, nearly $77 on average. And about two in five teens will chip in nearly $82, according to the NRF survey.

“These fashion-savvy kids are very much committed to starting the school year with the best locker decorations and the best sneakers and the best graphic T-shirts, and if mom and dad only agree to buy a few of those things, they are going to be sure to go in for the rest of the items they want,” said Kathy Grannis Allen, an NRF spokeswoman. “These teenagers and pre-teens … really want to have a role in what they wear and what they show up to school with.”

Analysts are expecting a highly competitive season. In a recent Retail Metrics report showing that few retailers beat sales expectations in July, Perkins noted that sales gains likely will be difficult to come by during the school buying season.

“The consumer remains particularly cautious,” Perkins said, even as economic news has improved in some areas, such as auto sales. “Consumers are not seeing much in the way of wage gains.”

Shannon Lapadat, a stay-at-home mother of three, said she started school shopping in mid-July to try to stretch out her spending. Lapadat and her daughters, ages 8 and 6, and son, 3, strolled Target’s school supply section last week, stopping at bins filled with colored pencils, crayons and folders. She had already spent about $300 on book bags, supplies and shoes.

“And we still need clothes,” she said. “We’re doing this little by little, rather than one big purchase.”

Even amid the economic ups and downs, Stickline said sales at her Wee Chic shop have risen in each of the past few years.

Children “need something new every year,” she said. “They’re growing.”