I often times start a new notebook when I begin a new area. Like when I got my long range rifle - I wanted to keep track of all my range visits, weather conditions, how I was shooting, etc. And when I started reloading - how I loaded things, how they performed, the accuracy, and things like that. And then when I was trying to learn ukulele. Gotta have a record of every chord I learned, helpful tips from what I learned, blah, blah, blah.
Each notebook has about the first three pages used, then it goes blank after that.
I used to use "engineering journals". I don't know the real name for those. But they are bound books of note paper and the pages don't easily tear out. I guess that's the whole point. So you have a permanent record of the things you did and the results. Those notebooks suck. Because they are quite expensive, especially when you only use the first three pages of each one.
So after a while I moved to three ring binders. Those work better for me because you can delete, add, and rearrange sheets as you see fit. A perfect medium for the scatter-brained like myself. But three ring binders are large. You can get small cute little binders, but those cost more and finding the proper paper inserts for them can be challenging. All in all, not really worth it for only three pages of use.
So now I just do things in a note taking app on my phone. The app was free, and you can very easily delete those three page startups that are cluttering up the view.
But taking notes on a smartphone is a chore. I suck at those "on screen" fake keyboards. So mostly these days I just take pictures of things I want to remember with the smartphones camera. Then I spend a few hours searching through thousands of random and unrelated photos crammed together in the picture app on the phone every time I need to find something.