My animation teacher ALWAYS has us drawing the model for one 20 minute pose and 5 1 minute, and 5 30 second poses. At first I resented this and wanted to get to the "real" drawing and not waste time. I would even angrily caricature my nudes at first, since I hated doing this so much. Over time, however,I changed my mind, when I began to notice the gesture of my cartoons changing. Now I look forward to drawing nudes and really try hard to get it "right".