Stopping is a skill.
Good teams kill work that isn't working, openly and early, so the time goes to something that might.
How To Stop Well
Agree kill criteria up front
Decide what result would make you stop, before you start.
Show the evidence
Make it about the data, not about anyone's idea.
Name what was learned
Thank the team. Record the lesson. It wasn't wasted.
Redirect visibly
Tell stakeholders early, and show where the capacity goes.
Kill it clearly. Keep the lessons.