For me if its just a quick session after work as the sun is going down, I throw about 100 casts and if I get no action then I call it quits. If its gonna be partial day whipping, I usually fan out left, middle, right, take a few steps to the right and then go recycle back through left, middle right again. I work my way down the whipping area and when I hit the spot where I know theres no action, I work my way back the way I came.