I also keep a paper notebook for software engineering, but I find it less convenient than my old chemistry lab notebooks were. The problem is that in my software engineering job, I must alternate between tasks and meetings many times a day. So either I keep things strictly chronological and have a difficult time maintaining a usable table of contents, or I have a new page for each of the day's projects, at the cost of constantly jumping from page to page and inefficient use of the notebook's space. I've yet to find a happy solution.