For some, reading habits are sacred -- like, I have to leave about 30 pages at the end of a book before I finish it. I find that it leaves the perfect amount of story left, and I'm always able to get through it in one sitting, instead of splitting up the resolution. For others, they'll leave a book spread-eagle on the counter and forget about it for a week. The same philosophies apply to bookmarks; the kind of bookmark you use can say a lot about the kind of reader -- and person -- you are.
People who don't use bookmarks: How?