Both. Too much. I spend several thousand dollars a years on books, both physical books and my Kindle. As I've grown older, (I'm 66) I try to shift to physical books before bed because, much as I like reading a Kindle in bed in the dark, I'm beginning to think it interferes with my sleep pattern, causing me to wake early. On the other hand, I'm the kind of guy who always has 5 or 6 different things going at once, so a Kindle is a lifesaver.