All of my books are DRM-free (or can be made so) and I always bookmark typos for later correction because I re-read books and that stuff drives me crazy. I find that if I hit 10 bookmarks and am not absolutely loving the story, I bail.
I used to be one of these people who finished every book I started. But I have so many really, really good books on my TBR list that I simply don't have time for mediocrity. Life is too short to slog through books I am not enjoying. So the typo thing is one reason, but I find that I am more capricious now than I used to be, and I'll bail on a book if I just don't feel like reading it anymore too
