Agh, I hate to give you a glib answer here, but I'd have to say "as many screens as it takes to reliably progress people forward." I tend to think less in term

Agh, I hate to give you a glib answer here, but I'd have to say "as many screens as it takes to reliably progress people forward." I tend to think less in terms of screens and more in user momentum -- how quickly and substantially are they making progress in what they set out to do when they signed up?