I have never been very successful at keeping one notebook devoted to one thing. I've tried, many times. This notebook will only be for picture book ideas. This notebook is only for drawing scribble designs. This notebook is only for action lists (to do). This notebook ...yeah, it doesn't work. I tend to treat all paper as equal, and sometimes I draw in a notebook and sometimes on a scrap. Went through some piles of paper and notebooks stashed in a cabinet this weekend.