[soldeace]

For the best part of my life I use a controlled set of tags[1] rather than hierarchical categories. This is mostly due to the fact that stuff can be a lot of things at the same time.

That said, one of the best use cases for Johnny's system I've found is when you have to share an online drive with hundreds of people, where you can't use tags, and even if you could, there would be no consensus. Strangely, nowadays I can find my way around a huge project's online files quite easily just by the prefix numbers of each categorical level.

[1] https://karl-voit.at/2022/01/29/How-to-Use-Tags/