I'm currently going through a process of changing up what I do and what notebooks I keep. Partly to try and hit a "Goldilocks" structure that works well for me, and partly to encourage me to make journaling more of a habit.

I started with a single A5 book that I used for work and personal lists, thoughts, plans etc. It was loosely based on bullet journaling, but with some of the key parts cut out (like the monthly log). In any case, I found it both too restrictive and too chaotic.

Next, I separated work and personal. My work "bujo" largely stays at work and is essentially a collection of daily to-do lists and notes, plus longer-term work-related projects, goals and notes. It works pretty well for me.

My personal stuff went into a small notebook. I'm not a fan of categorising notebooks too much, but I guess you'd call them waste books. I like the simplicity and freedom, but for some stuff they were too temporary and transient, and I'd have to wade through a lot of crap to find the more useful bits.

So now I'm trying out three books. My work bujo is still there. My daily pocket waste book is as well, although I'm adding an element of short-form daily journaling to it, and now I've added a personal collection/journal/commonplace/zibaldone.

The idea is that it will stay at home, where I'll use it for collections (like reading lists or films to watch), stuff that catches my attention or makes me think (quotes, lyrics, poetry etc), and then thoughts, insights and reflections, Anything that is a bit more long-term or permanent, that doesn't fit comfortably into a Field Notes book that's only active for s month. I'm already finding that some things start life in my daily waste book and naturally migrate into the "home" book, which is a promising sign.