I never replace mine unless I am testing a different brand and don't like it. I re-spool when it gets shorter due to reties/break-offs which is seldom. I have some Spiderwire on my Trap rod that is at least 8 years old-it's just like the bunny rabbit ,"it keeps going, going, going-----------.
Sometimes I'll change it out for a different pound test, but I wrap it on a spare line spool for re-use.
I carry a short piece of 3/4" wooden dowell to break the line. Sometimes I'll use the net handle.
Always try to break it off instead of cutting it off as the less you leave in the water the better it is for water fowl, aquatic life and your fellow fishermen.