I think it depends on the flyfisher. I've fished with people who hit a pocket or run with two casts and then move to the next hole, and I've fished with people that can park on one good looking run for an hour and a half without moving. . .
I usually try to leave someone( that I'm passing) at least 500-1000 yards, which means I'm not going to be fishing for another 20 minutes at the rate I hike.