Well it is about time that someone replied. I discovered you and your work independent of this site. Yes when to stop? When I can't wait to start the next inspiration that is in my mental queue (of which there are so many fighting to be first). My late start in art may well mean that I run out of living with a still active mind and too few paintings made. So I finish the painting...leave it on the easel overnight...give it a thorough detailed once-over the following morning...and sign it...then digitally photograph it. Then share it with you alll on this site. Any strengths or weaknesses of that work are recorded in it's computer image file...then the next time I can refer to this similar image...etc. There is a Thread on the forum, here "When to Stop"