Exactly, .matthew. From an author's perspective, a chapter break is offering the reader an excuse to put down the book. Thrillers excel at putting cliffhangers at chapter's end, to keep you turning pages. And I have a tendency to break the chapter when the action subsides. When editing, I deliberately look for chapters that end with my characters going to sleep or the like, then try to find other ways to define the chapter. Going to sleep is rarely an important part of the narrative. <g>