To answer your question, college classes usually carry a small bag, not a big bag. Everything you use is casually put in a small bag, so I think it's useless to bring too many things, so putting all the useful things in a small bag will make the class clearer and faster. No matter what you take, it's easy to carry, and taking the bus is slow and labor-saving, so all the useful things in the bag are put in the small bag.