Great article about the benefits of building sketches in to your design process. I couldn't agree more.

“Learning from sketches is based largely on the ambiguous nature of their representation. That is, they do not specify everything and lend themselves to, and encourage, various interpretations that were not consciously integrated into them by their creator.”

http://uxdesign.smashingmagazine.com/2013/06/24/sketching-for-better-mobile-experiences/