I have found my self drawing out paintings more and more and more lately, for a while when I was doing a portrait I would literately just draw a few guidelines for eyes and proportions and that was is, the rest would come with the paint. But the last few dozen I have been setting up I am lacking the confidence? in my self to do that, I have been fully rendering the face, shadows and even tones as well, which is a bad thing I guess, it takes a lot of the "guess" work out of the painting, yet it does give way more issues with covering the drawing, I seal it with a sealer but having a fully rendered drawing on canvas can be hard to cover. So when is enough enough and do you start painting. I think for me, I started out drawing portraits and then got in to painting, so I am by far a better draftsman then a painter, I feel I need the more elaborate sketch.