cut off the faded and be good to go.
Synthetic line dies from:
sunlight !! most have a UV coating (that color they are is usualy the coating as naturally they are a tanish color) but that is the most common killer.
Next is abrasion. and I do not mean "drug across a rock" abrasion, I mean DIRTY. Dirt/mud gets in the fibers and when under load abrades and cuts the individual fibers. Then you have the "drug across a rock" abrasion.
Solution for both = tubular nylon used as a chaff guard.
Get some 1" tubular nylon in a couple 3' lengths from a rope place/climbing store/mil surpluss and slide it over the line. keep this on the first 10' or so of the line or whatever the last wrap length is. So when you spool it in the "last wrap" is now covered in tubular nylon and protected from sunlight. Also you have a couple moveable chaff guards that you can side down the line to wherever the line is going to hit a rock/tree/small woodland critter/whatever.
Plus you can get tubular nylon in any color to match your JK
I also keep 1' squares of carpet remnants (free from carpet stores) under the drivers seat to act as "hardcore" chaff guards when I know I am dragging the line over something rough. They also work nice to sit on instead of the mud when doing trail repairs
Now as for dirt: I will pull the line all the way out into a bucket of warm soapy water, wash well, rince well, lay it out in the driveway to dry and then respool it. Or for when its real bad or I am lazy I will pull the complete line, stuff in a mesh bag and run through the washing machine.
I replace line when it is severly damaged, brittle or fuzzy to the point it does not spool right.