I follow these simple rules and encourage my colleagues to do so

1. If I'm just shuffling jsons, then yes, the code should be self documented. If it's not, the code should be rewritten.
2. If I implement some complex logic or algorithm, then the documentation should be written both to tests and in the code. Tests should be as dull as possible.
3. If I write multithreading, the start, interruption, end, and shared variables should be clearly indicated by all means that I have: comment, documentation, code clearness. Tests should be repeated and waits should not be over 50ms.