What's this thread for?
If you are not sure, look at the title. That's what it's for after all.
But that's not what happens with our threads, does it?
One thing leads to another and a thread (whether it's email or Slack or AI) goes from a sales conversation to finding a pet sitter.
The practice is to stop the thread when the title isn't matching the conversation. Start a new thread with a relevant title.
It helps everyone. It leads to short, effective threads. It's easy to search for. And anyone reading can get the context just by reading the title.
And if someone asks why, you can point them here.