Are We Done Yet? (An Informal Poll)

Yesterday Eric Orchard posted a wonderful step-by-step on how he creates a painting. (Check it out-- his work is gorgeous!) I was curious about how he knew when a piece was finished, because that's something I always struggle with both in my illustration and my writing. Here was his answer:

I can't say specifically when I'm done with a painting. I think it has to do with contrast and tone. The composition looks done to me when the forms jump out and are distinct against the negative space and when the tone/shading looks convincingly three dimensional.

I love keeping thoughts like this in mind when I'm working (thus my addiction to art/writing/creativity books...) It's a great way to keep your work evolving.

So-- here's my informal poll: How do you know when you're done with a piece of art? Or writing? Or are they really ever "finished" at all? I'd love to hear your thoughts-- I'll post them all later!