This one seems obvious I suppose, except that I only recently actually did it for the first time.
Braided lines like PowerPro and Tufline are more expensive than monofiliment but last much longer. Eventually though, they'll need to be changed. If your spool of braided line is getting frayed on the end, simply cut off a few feet and retie your mono leader. If the line is getting worn overall, take your rod and reel to your local park on a weekday when the crowds are down, tie the end to a tree, flip your bail or hit your release lever or thumb bar, and walk away until all the line is off the reel. Then cut it, walk back to the end where you tied it to the tree, run it back through your guides and re-attach it to your reel arbor. Spool it back onto your reel in reverse. As you reel it back onto the spool, let the far end slide free on the grass. This will help take out any line twist. When you're finished, the worn end is buried under some nice, clean, fresh, bright colored line. Just like new.

Braided line like PowerPro looses its color and turns white with use. This is because the color material that is used cannot penetrate the line material. It simply encapsulates it, making it easy to wear off. The PowerPro website recommends recoloring the faded line with a Magic Marker of your color choice. I mention this because your line may look "worn" when only the color is faded.
Oh, and be sure if you reverse and respool your line, that you pick up any remaining pieces you have cut. Little piles of old braided line can be deadly to wildlife and pets.
zonker