Elementary-school backpacks need to be roomy enough to hold, at minimum, a standard two-pocket folder, a book, lunch, and a sweatshirt. Older elementary- and middle-school students will likely also need to pack a binder, notebooks, and, increasingly, a laptop, tablet, or smartphone. My kids also packed the bags with their personal belongings (down to their favorite pens and pencils in the pen holders). For several weeks, they dragged, lugged, and carelessly tossed the fully loaded backpacks around and rated them for comfort and ease of use. They also ranked their favorite designs, noting the ones they most definitely would want to take to school.