Abstract in Progress: Part 2

I don't know how hard it is for other artists, but I find it difficult to know when to call a painting finished. This challenge seems even bigger for non-objective expressionist art where the only frames of reference to define "finished" are completely inapplicable. It is not the purpose of abstract art to "look like something". So when is it done?

The unfinished abstract I posted a few days ago continues to evolve and I am not sure where it will go. Your ideas and comments are most welcome.

Understanding, Acryic on canvas, 18"x24", Not for sale