The life expectancy of a fly line is directly related to use. Sun, Grim, Storage and Use degrade a fly line. This is not accurate, but if the line is not abused and not reasonably maintained, it should last 250" days of use. For a full-time fly fishing guide, this can be a season or two.
The 2-year mark really should be the end of the line (no pun intended) for any tippet reel. But, if you feel that you are struggling to get more than one season out of your tippet before it becomes too brittle, we have some tips for you. This is due to minor scratches or cuts in the line coating that allow the line to soak in water. Sunlight and high temperatures can dramatically weaken these lines, and the most popular places to store fishing gear are often the most problematic.
Fishing from a boat can put you in the best possible position to fish, but it has one of the biggest threats of damaging your fishing line. Most fly lines are coated with PVC, and any residual chemicals on the hands could reduce the life of the line by deteriorating that coating. For example, if you have already used the line in the previous year, you should take some time to examine it for nicks and imperfections before using it in another run. But as the years have passed, its line has been exposed to sunlight, algae, debris abrasion and just general wear and tear.
They have been leading the way in manufacturing some of the best flight lines on the market and this is no different. Once anglers start watching their floating line sink, or they notice the line catching on the guides, they think it's time to change it. Unless you're guiding or in the water more than 200 days a year, you don't usually want to replace your fly line every season. This means that the ridges run the entire length of the line and reduce the surface area of the line that contacts the rod guides.
A fly line is designed to be smooth, so you can shoot through the guides of a fly rod and this friction impedes your ability to do so. Once the fly line has sufficient wear, the dressing will no longer be effective and the line will need to be replaced. Which means that if you are the type of angler who has an average of 4 fishing trips per month and cleans your line regularly, then you should get about 4 years of use from your line. Most of the time you will be surprised at how well your line works after cleaning it just once.
Fly fishing can quickly become an expensive hobby, and the fly line contributes to it, but it doesn't have to be. There's only one way to make sure your tippet doesn't become brittle, and that is to use it all before it goes bad.