Weight forward floating fly fishing line in 5, 7 and 9 weight. Fly fishing line should probably be changed more frequently than the typical fly fisher does. One of the main reasons for this is cost. All fly lines will eventually become more difficult to cast with age and use. Dirt will get embedded into the coating. Microscopic cracks will happen in the coating. These cause friction as the line comes into contact with the rod guides resulting in reduced casting distance and accuracy. Line memory can also make your outing more challenging as the line ages on the reel spool. Why not change your line more frequently and eliminate those challenges?