NEW YORK ( TheStreet) - Retailers banking on back-to-school sales to jump-start revenue heading into the fall may be in for an unpleasant surprised. According to an annual survey by the National Retail Federation and Prosper Insights & Analytics, back-to-school sales this year are expected to fall compared to last year. After strong spending in 2012, families with school-age children are expected to spend an average of $634.78 on apparel, shoes, supplies and electronics, 8% less than they spent in 2012, the survey forecasts. Total spending on back-to-school is expected to reach $26.7 billion. Total back-to-school and back-to-college spending combined will reach $72.5 billion, the survey says. "The good news is that consumers are spending, but they are doing so with cost and practicality in mind. Having splurged on their growing children's needs last year, parents will ask their kids to reuse what they can for the upcoming school season," NRF President and CEO Matthew Shay said in a statement. "As they continue to grapple with the impact of increased payroll taxes, Americans will look to cut corners where they can, but will buy what their kids need. It's important to note, however, that spending levels are still well above where they were a few years ago." On a positive note, consumers are already out shopping for school items. The survey found that 24% of respondents said they will begin shopping at least two months before school begins - the highest percentage seen in the survey's 11-year history. "We continue to see a shift in shopping patterns during big spending 'events', where consumers typically head out early to take advantage of fresh inventory options and initial markdowns, then see a lull only to rev back up again when final sales appear," said Prosper Consumer Insights Director Pam Goodfellow. "Hoping to spread out their budgets, but still reap the benefits of getting the products their children want, parents this back-to-school season will comparison shop online and around town at their child's favorite stores, potentially even more than once, as they seek to find bargains and products that offer the best value."