Here's a breakdown:
When it might be appropriate:
* Formal business letters: Especially if you are writing to someone you don't know well, a formal closing like "Cordially yours" might be appropriate.
* Letters of complaint or criticism: A formal closing can add a sense of seriousness to the tone of the letter.
When it's not appropriate:
* Casual emails or letters: In informal communication, it can seem overly formal and awkward.
* Most personal correspondence: It's not appropriate for personal letters, emails, or notes to friends or family.
Better alternatives:
* Sincerely,
* Best regards,
* Thanks,
* Warmly,
* All the best,
Ultimately, the best closing depends on your audience and the tone of your communication.
If you're unsure, it's always better to err on the side of formality and choose a more neutral closing.