A code comment is useful when it adds context that cannot be understood from the code alone. Simply repeating what the code does creates noise without helping the next person make a change safely. The most valuable comments explain why a particular decision was made.
Source: [Dev.to](https://dev.to/tanya_kamenskih_fae915d43/why-comments-should-explain-the-reason-not-repeat-the-decision-32hg)