Couple different kinds of notes, but I think this covers most of my use cases

I use google keep for small reminders, things I want to look up later, grocery lists to share with my wife, etc.

I keep a couple field notes notebooks around in my car and bag for things I want to make a physical note of, especially things I need to sketch out (I am no artist by any stretch of the imagination but I’m a capable DIYer and I sometimes need to sketch out the thing I’m building/fixing) while I’m out and about before I forget about them. I like the size of them, and the dot grid lends itself well to the kind of notes and sketches I use them for.

I also have some sketches of the rooms in my house in those books, list of some furniture dimensions, so when I’m out shopping with my wife and she asks “do you think this will fit in our dining room?” I can tell her definitively yes or no.

It also has a list of the bulbs, tires, wiper blades, air filters, etc. that our cars use, so I can reference them quickly while out shopping, it’s quicker to just flip to the back page of my little notebook than to try to look it up on my phone from the aisle at AutoZone or Walmart.

I also have a rite in the rain notebook I keep with my tools, it’s fairly rugged and waterproof, mostly ends up getting used for scribbling down a list of stuff I need to get from the hardware store in the middle of a project. Went with that one because I’m pretty likely to be using it when I’m wet or dirty, outside in the mud, under a leaking sink, etc. while I’m halfway through a project.

I keep another one of those with my camping supplies.

I have a pad of graph paper at my workbench, I like it for sketching things out, same as I like the dot grid in the field notes books, but this one doesn’t have to travel around with me or pull double duty for written notes, so I could go bigger and cheaper

We also did our kitchen cabinets in blackboard paint, so my wife and I can leave notes to each other on there, mostly reminders to empty the dishwasher and such.