Fishing Tip of the Week: Monofilament and copolymer fishing lines are still great lines to use, but anglers should realize that they are susceptible to UV damage. ...more UV rays will deteriorate mono and copolymer much faster than they will fluorocarbon and braid. Line left out in the sun will lose its tensile strength much faster than line stored in a cool dark place. The best way to prolong the life of your line is to store it in an opaque container or cabinet that is in a cool area. Mono should be changed off the spool at least every two months to maintain tensile strength for when that big one bites.