Obviously I work in series. I'll have Meg (or Moo, as I call her) pose for about an hour, while I shoot with my Nikon D80. Usually after an hour we're both bored and lacking interest. I'll write her a check, and go home with 200-300 photos, of which maybe 10 or 20 will have images that I can get excited about. This should keep me busy for a few weeks. When I get bored with the series, I'll set up another photo shoot.