A lot of us are pretty bad with procrastinating so as soon as those bags/boxes of school supplies are in your hands, they should be packed away. That way, you won’t have to keep telling yourself “I’ll do it later” and before you know it you’ll have run out of time.
Personally, I’ve never had a problem with this because packing items away has always been oddly satisfying to me. For the most part, it’s smart to get your books early to save money on not having to buy new books although there are some teachers that will admit to not using the book. I would suggest if you can, talking to your teacher about this or at least rent the books so you can just send them back.