I buy text books, not as often as I did because of things like Lynda but I do from time to time. The first thing I do is to cut the book with an automatic saw and give the pages to my amazing Fujitsu automatic scanner.
Then I store the book on a box far away in a storage room.
This way I have a 100% DRM free book I can read whenever I want and weights 0 grams, and I can travel to other countries with it. Most of the time(when buying multiple books) the tree killer version is cheaper than the DRM ebook one, and it does not have your name in all the pages like some bastards do.
Some books never will have a DRM free ebook ever.