I haven't yet, but after season I am due to put on a new loop. I use material thats better than what my shop put on mine originally and tie my own on. I trust myself.........maybe thats not a good thing[8D].

If you see any fraying, replace it! If the burn end balls are not big enough and burnt right to begin with....do it again until its right. IMO, a release that has an unseen nick or a sharp edge is a culprit along with an improperly tied loop. I've only heard a couple of stories and have never witnessed anyone breaking one while shooting or pulling a loop back.