My friend Emily (who runs the blog Just Another Emily Anne) published a post awhile ago which asked the burning question:
When is an idea good enough to pursue?
As artists, we must figure out which ideas to keep––and which to toss.
Maybe, as Emily muses, an idea is worth keeping if you work at it with all your might, and make it mature and grow.
See her full post here: When is an idea good enough to pursue?