I started buying custom printed notebooks from the scientific journal companies. For $10 a journal you can get a very niche hard cover journal, with page numbe

I started buying custom printed notebooks from the scientific journal companies. For $10 a journal you can get a very niche hard cover journal, with page numbers (if you like), plain, ruled or grid paper, and embossed with your name (or whatever). It's so satisfying. Combine that with a nice fountain pen and ink and it's quite the experience. It's my proffered way to take notes, think through problems.