When to use it
Use it whenever you get a task with any ambiguity: the format, the audience, the deadline. Repeating the key points back takes ten seconds and catches mistakes before you've done the work. Most people appreciate it.
Example
Manager: “Can you pull together something for leadership on the pilot?”
You: “Let me play that back: a one-page summary for leadership, by Friday. Right?”
Manager: “Yes, but Thursday if you can.”
In an email or Slack message
After a verbal request, send a short recap: “Confirming: one-page pilot summary for leadership, by Thursday. Let me know if I've missed anything.”