RE: string loop
Yes it does need to be change every so often. Check it as you would a bow string for wear and tear. If it looks worn change it, especially from a safety standpoint.
I had one that the batting in the middle of the string loop, which gives it bulk, broke free. This allowed it to slip through my release at about half draw. Luckily no one was injured, but I did lose the arrow in a pasture.