Monofilament fishing line is cheap and should be replaced every year. Sunlight (UV) is the biggest enemy of mono and that includes fluorescent lighting so be careful where it is stored on or off the reel.

Fireline, braids and fusion lines are expensive by comparison and will last much longer before they need replacement. Water, heat and sunlight does not degrade the stuff like it does with mono. After two or three seasons I will remove and reverse fireline on the spool and get another couple of seasons out of it before I will replace it. What will degrade fireline is abrasion so watch for fraying either from rough use in rocky locations or bad line guides on the rod or reel. If the line starts looking fuzzy soon after you start using it suspect the rod or the reel and fix the problem or it will get expensive replacing line or losing fish.

My early experience with fluorocarbon line was similar to MT's. I started with Berkeley Vanish and could not for the life of me tie consistently good knots. I gave up and haven't gone back to the stuff. I would expect there have been improvements so it is probably time to give the stuff a try again but there are just so many other options out there.

Anybody get their hands on Nanofil yet?