I usually buy both an e-book and a paper version of books I want to learn from. Most of my reading is done on the paper one. I like to re-read certain chapters

I usually buy both an e-book and a paper version of books I want to learn from. Most of my reading is done on the paper one. I like to re-read certain chapters or sections at really random times and places so that's where the e-book comes in. It's a more pricey scheme but I find it really helpful for me.