Ernest Hemingway, one of the most prolific American authors, had a habit of routinely leaving his work unfinished each night before bed. He would just stop writing mid-chapter, mid-paragraph, and mid-sentence. This practice gave his technical and physical mind a chance to rest before it got sloppy. More importantly, though, it kept his creative appetite whetted and active throughout the night so that in the morning he could pick up where he left off with renewed zeal. We can learn from Hemingway about leaving a little on the table when it comes to our pursuits.
It is often wise to quit while you are ahead. This strategy is called