When I was in high school (Class of 1969 - yes, it's been 40 years), we carried our books on our hips with one arm or close to our chest with both arms, sans backpack (not yet though of) or book satchel (which was really old-fashioned). Depending on the chosen carry-method, we always had one - and only one - arm free to open doors and lockers, pick up assignments or papers as we entered/left class, and smooth down our hair or skirt. Not much leeway for trouble, having only one idle hand.
Now, there was a very distinct method to stacking our books so that we could carry them comfortably with one arm to and from class, bus/car, and home. The foundation upon which our loosely carried bundle was built was a large rigid notebook filled with loose-leaf paper, dividers, and often a little plastic pouch that held pens, pencils, and protractor. Then, depending on the size of our history, English/literature, math, and science books, we stacked accordingly - narrower books could be placed side by side on the notebook, with wider tomes placed underneath or on top to stabilize the stack.
We girls also had our purses (John Romaine, natch - no shoulder bags) clasped firmly in our book-carrying hand. And sometimes there was a lunch sack (brown paper, once we outgrew our Howdy Doody lunchboxes). I don't remember it being a big deal. We managed.
But we didn't carry all of our books around all the time. That's what lockers were for - no matter how far-flung from scheduled classes. Usually, we carried the ever-present notebook with a book or two to tide us through a couple of classes. Our bundles increased as we left for home at the end of the day, but, again, we usually didn't have to carry every single book - usually two or three were all we needed.
Contrast that with today's Bag People. Poor kids. It seems reasonable to believe that this new bag-method is more efficient that the hippy-method, but I don't think it is. Enormous backpacks stuffed beyond all reason (what is in there?), hoisted upon young backs, causing them to lean forward just to get enough traction to move. Plus, backpacks leave both hands free to, well, get into all kinds of trouble that could be avoided if left to the devices of only one-handed-chaos-causing. Think about it. My career advice to today's students: chiropractor.
I don't know which book-carrying way is better. I do know that I don't envy today's school kids their beasts of burden. Oh. And I do know that our clothes were cuter. Sayin'.