Every few years a company stops making the app your notes live in. The files stay on the drive, the app that can read them does not, and what you actually own stops being a philosophical question and becomes a practical one.
A file is not the same thing as access
A file format is a promise that some piece of software will keep existing to read it. Plain text makes a much smaller promise: that any computer will open it, now or in twenty years, with no licence, no version and no migration.
Markdown is the compromise that held
Markdown was designed to be readable before anything renders it, which is why it spread so far. Write a heading with a hash and a list with a dash and you get a file that is legible raw and formatted later, in a browser, an editor, or a static site generator.
What plain text is good at
- Notes and drafts that mainly need to be readable rather than designed.
- Configuration, documentation and README files that live next to code.
- Anything you expect to still care about after the tool you wrote it in has been discontinued.
The habit matters more than the format
Keep notes as files the machine can already open, name them so they can be found without searching, and back them up somewhere that is not one company's account. Plain text is not nostalgia. It is the only format with no expiry date.