A successful fly fisherman is prepared to fish a variety of conditions and is able to adapt his or her technique to present a fly in the "zone". This can only be done with a variety of lines or sink systems. A floating line has many applications, including nymph fishing, dry fly fishing, and shallow water fishing. A sink tip line or Streamer Express line is necessary for streamer fishing in deeper water. Saltwater lines have a stiffer core and won't soften in warmer conditions. Having several lines will enable you to customize your presentation and improve your success on the water. A spare spool on your favorite reel donned with a second line increases your ability to get the job done!