Alot of factors can influence string life, humidty, use, wax, dragging it through brush or hanging on a hook in a tree.

However, most strings break under the serving, either at the nock or at a severe angle on the cam, here you can't see.

Have a friend punch you in the face, this could be what a string breaking feels like, except it will be your own release hand, how fun is that?

I change mine every year just after hunting season, or whenever it looks worn, but I make my own strings. change it out and ask for the original string back, when you get it back, take off the serving, see how different it looks under there.