When to Stop

I always wonder when is it time to stop working on a drawing. Other than an exhibition date approaching or extreme boredom with the image, I always want to add more.  Since recently returning to the studio I have been treating my drawings if they are precious.  I hesitate to work on them or try new things. I hate feeling that way, it is as if my hands are tied behind my back. 

I already overworked this drawing last week with too much spray paint. I still hesitate to add more, even though I considered it wasted. 

When is more really more and when is more too much? 

This continues to run through my mind.  I will walk away from this drawing for a day or two until I feel more confident in my choices.