The advantage of using 3.5x5.5 48-page notebooklets for work notes: they’re small enough that I can just have one for each subproject and not worry about wasting pages, and they’re not so long that they’re miserable to scan on a flatbed in their entirety when they’re full, and filling up provides a natural “stop and scan me” point when I procrastinate when using larger notebooks.
I am a slut for Field Notes is most of what I’m saying I think.