Our kids spend a third of their day in school, but the work doesn't stop there. Perhaps the most dreaded part of back-to-school, for both students and their parents, is the return of homework.

Dennis Tokarzewski, ThinkStock

Depending on the workload, some students could spend hours on their out-of-school assignments, and it's an even heavier burden for families dealing with children who participate in extracurricular activities.

New Jersey schools say homework is vital in making sure students master what's taught in the classroom, but at the same time, many make an effort to limit a student's workload after school.

Patricia Wright, executive director of the New Jersey Principals and Supervisors Association, said policies on homework are developed at the local level, and some of those policies specifically address a time limit on assignments.

"It's approached differently in every system and every school district," Wright said. "That depends a lot on the developmental level of the students and the content of the courses that they're taking."

A sample policy from the New Jersey School Boards Association, which any district can follow, states that "teachers must use discretion in deciding the number and length of assignments." It also suggests that homework not be used for punitive reasons.

"We believe that homework relevant to materials presented in class provides an opportunity to broaden, deepen or reinforce the pupil's knowledge," said NJSBA's Jeanette Rundquist.

Some schools, such as New Milford High School, have adopted a "flipped" approach to educating students. They learn the lessons at home through online resources, and use their time in class to complete assignments that would normally be used for homework purposes.

An in-depth analysis from the Brookings Institution, released in March, found the amount of homework has not changed much over the past few decades.