when i am curious i know how long my line is and i see how much running line is still on the reel. i don't count the leader.
i think a much better question is how far away is the fish and where do you find the best angle to present a fly.
there are several runs on the North Umpqua i fish twice, the first pass i fish from one position covering the whole run with long casts
then i wade down it picking it apart seam by seam.. i hook far more fish on the second pass.
"Never be afraid to show love" Frank Moore