It just occurred to me that I would probably benefit from placing my bookmarks a little before where I actually stop reading. Oftentimes, when I return to a book, I realize I acutally forgot what happened at the last moment and need a refresher. This additional context seems doubly useful for academic books, where stuff tends to build, and having overlapping review is very important.
Generally this stuff is in the vein of the whole "don't just read books from front to back" sort of attitude. Overlapping readings might be pretty beneficial.