How do you know when to stop?

When is a painting finished? That is the hardest thing at times, to know when to stop. There is usually a point when adding more makes less. I have been working longer than usual with my latest painting, adding, changing, putting it away, bringing it back out, looking at it, ignoring it. It is different, it is large, it is almost realistic, except the view doesn't exist in reality.

My back hurts and my eyes are sore, that is usually a sign to stop no matter if the painting is finished or not. Maybe this time it is done, ready to be signed.

Maybe....