Original backpack from L.L. Bean. (Courtesy of L.L. Bean)

It’s hard to think about school supplies while you’re still enjoying homework-free days at the pool. But the new academic year will be here in a few weeks, and one thing that almost every student needs is a good backpack.

Whether your child is on the hunt for a backpack with a favorite cartoon character or in a preferred color, it’s important to help him choose one that is the right size and shape for his body and what he needs to carry.

Depending on his activity schedule, your child could be lugging that bag around from 7 a.m. to 7 p.m. five days a week, said Pam Jones, a senior designer at L.L. Bean. And he might be carrying sports equipment, snacks and a laptop, in addition to notebooks, pencils and paper.

What’s new:

Shapelier profiles: The size of most backpacks is still determined by the standard three-ring binder, Jones said. But as students carry more devices and fewer old-school textbooks, the scale and profile of the bags have changed, and they have become more “shapely” and less bulky, she said.

Backpack from L.L. Bean in the Sport pack style. (Courtesy of L.L. Bean/STUDIO1912)

Room for technology: More backpacks come with compartments specifically designed to hold phones or other electronic devices. Some backpacks have places to thread a cord for headphones from the child’s ears to the music player in the pack.

Care and usage tips:

Don’t machine-wash your pack: Jones said putting a backpack through a washer and dryer could damage reflective coating and foam padding. Instead, immerse the pack in warm water with dish detergent and scrub it with a stiff brush or abrasive sponge.

Wear the pack correctly: Karen Jacobs, national spokeswoman for the American Occupational Therapy Association’s National School Backpack Awareness Initiative, said children should always use both straps. They should wear the pack fully on their backs, rather than on one shoulder. She recommends packs that have straps across the chest and waist to help distribute the weight appropriately. She said padded back panels and straps also help cushion the load.

Don’t overload: A backpack should not weigh more than 10 percent of your child’s body weight, Jacobs said. Put the bag on your bathroom scale to check the weight. If you find that your child is consistently exceeding the 10 percent rule, consider a wheeled backpack or keeping a second set of textbooks at home. If your child takes a water bottle to school, have him take it empty, then fill it up at the water fountain when he arrives, to cut down on extra weight.

Low, Medium, High options:

We asked L.L. Bean’s Pam Jones to recommend three backpacks at different price points. Here are her suggestions.

Original Book Pack . For children age 7 and older. Made of nylon, the basic bag has reflective material on the front and the straps to improve the child’s visibility at night. The back panel and straps are padded. It has one main compartment and two smaller front pockets and comes in four solid colors and six prints. $34.95.

Deluxe Book Pack . For children age 10 and older. Made of weather-resistant fabric, the deluxe pack also has reflective material on the front and straps. It has a padded back panel and straps, and a waist belt to help distribute the weight of the pack. There are two main compartments and two smaller compartments, and it has an opening to thread an audio cord to allow easy access between headphones and a music device. It comes in eight solid colors and seven prints. $39.95.

Sport Pack . For children age 9 and older. This pack combines the features of a trail pack with a backpack. It has a large main compartment, a section for organizing small items and two mesh side pockets for water bottles. Made of ripstop nylon fabric, the pack has a padded back panel and shoulder straps and reflective trim. It comes in five colors. $49.95.

Shop Smart:

Karen Jacobs, an occupational therapist, offered several suggestions for parents who are looking for a book bag for their child.

1. One size doesn’t fit all. Don’t buy a larger backpack with the intention of your child growing into it. It’s important to choose one that fits your child well right now. The backpack should sit just below his shoulder blades and end right at the waist. Adjust the shoulder straps so it fits snugly. Check your child’s backpack each summer to make sure it still fits.

2. Consider buying in person instead of online. Not only does this allow you to check the fit, you can also see how much the pack alone weighs and test it to make sure the things you need to carry will fit comfortably inside.

3. Go for breathable materials. Choose a backpack made from lightweight fabric instead of leather. A heavier material means a heavier pack, even before you start loading it with books and supplies.

Find Handy Guides on portable play yards, bikes, cribs, strollers, car seats and outdoor play sets at washingtonpost.com/parenting .