Ropes break because they rub on a certain point in the routing, which cuts the strands down (fraying) and they break.
To avoid this, once or twice a year, I will pull the rope up about 2 inches through the handle and re-tie it. This keeps the same spots from rubbing down to nothing and the rope breaking. And, yes, look for any sharp edges and sand those down if necessary. I haven't had a rope break in over 20 years after regularly trimming them like this.
Stock ropes are generally decent...but they will fray into nothing if left alone on the rub spots.