Forcing myself to finish a drawing in under 30 minutes has been a real eye opener artwise for me, it doesn't let you get caught up on the details: you are forced to imply rather than detail: saving the detail only for what is deemed most important. Sure I may add a few tweaks and some last 30 second details, but the point stays I am only allowed 30 minutes. After this my next goal will be to work up to drawing the full body. Jeremy Bernal can do it in 20, I think I can do 30.