I have DNFed about 30 books since I started keeping track on Goodreads. I used to be
highly reluctant not to finish a book. I'd like to think I've since gotten better about not giving too much time to books I don't like--eight of the books are from just this year. Now I say I'll give it up to 10% or 50 pages to convince me to finish it.
My main reason for DNFing is similar to why I pick up books -- I am a mood reader who hardly ever knows what I'm going to read in advance. Mostly I just pick something off my Goodreads or Calibre in random sort mode and go from there. So either I am not in the right mood for a book, I am bored by it, or do not enjoy the writer's style / the content.
Being able to download samples of ebooks has saved me a ton of money. I can't tell you how many samples I've put down over the years. I don't keep track of those
