I use a backpack, and use my locker too. Like other people have said as well, with all the books and binders I have to carry around, I need both! Last year I had approx. two textbooks per class, as well as one binder. Multiply that times 5 classes (excluding PE) and you can see that there is no way I can carry it all around all day! Having a backpack in class is better too, cuz then I can keep a brush, mints, pencils, pens, highlighters, and tons of other stuff with me all day, without having to stop at my locker for them!