You are allowed to finish before you are exhausted.
Exhaustion provides a very obvious stopping signal. Completion can be quieter. You have done what you intended, but there is still energy left, so you search for another thing to justify using it up.
Try deciding what finished means before you begin. The remaining energy can belong to dinner, conversation, or nothing in particular. Some days genuinely demand more than you planned. On days that do not, you need not create an emergency to earn permission to stop.
What would tell you that today's work is done before your body has to?