At a software engineering internship in 2006, my mentor told me that he kept a paper engineering journal that he put notes in every day as he worked on problems. He gave me one, too. I followed that habit during all of my internships.

Then ~4 years later, I started working as a full-time software engineer. A few months into working, I stopped using a paper notebook. I think part of the reason is that I had a better tool: the bug tracker. Pretty much every assignment I got had a corresponding entry in a bug tracking database. I started keeping the notes of my investigations in bug reports directly so there would be a central and shared source of truth. A mentor at this job said "some of the best engineers" put frequent clear updates in their bugs.

My personal projects had always been note-free, though. Unfortunately, I didn't bring the same problem-solving-and-knowledge-capturing discipline to personal projects until ~2016. That's a whole decade after learning the value of an engineering journal at work!

Now, even for informal personal projects, I keep a notes.txt file in the git repository.

Here's an excerpt from notes.txt for this website (which is a personal side-project of its own):

(You can see the full notes.txt for the project here.)

I use notes.txt to capture:

- Problems I'm running into
- Thoughts on what might be happening
- Potential solutions to explore
- The solution that worked
- Useful links and other research
- Useful commands
- The full steps required to do something novel (for example: getting a 3rd party open source library to build and install correctly)
- Features I want to add
- The bug list
    - For a simple side-project a text bug list embedded in my notes is much easier than a full bug tracker