I have taken to carrying three notebooks. Here’s how (or better, when) I use them.
Before it happens
I use a Hobonichi Techo Planner for scheduling and planning. It’s loaded with calendars and dated pages.
The Hobonichi is a wonderful, easy-to-carry planner that uses Tomoe River paper; my favorite. I record all event-based information in one. On each day’s page I write a list of things relevant to that day. I sometimes include a small sketch representing the day.
While it’s happening
I use a Field Notes notebook to jot things down while I’m away from a desk.
The Field Notes notebook fits in my pocket, so I always have it with me. With it, I can quickly capture things any time.
After it happens
I use a Leuchtturm1917 notebook to record notes and keep lists. It’s a modified Bullet Journal.
The Leuchtturm is great for longer-form notes and lists. It’s my bullet journal and where I collect things captured in the Field Notes notebook once I’m back at my desk.
My notebook configuration changes regularly, but I like where things are now.