Evergreen notes should be atomic
To make it easier to connect the note or topic to other notes or topics.
If, for instance, all the notes you make about a book you read is in a note for that particular book. Concepts you might extract from it will be hard to link to similar concepts from other sources.
Title is stolen from Andy Matuschak’s notes
‘It’s best to create notes which are only about one thing – but which, as much as possible, capture the entirety of that thing.’