APC props will fatigue if they are overstressed. If you look closely at the blades there will be whitish areas about 1/3-1/2 the way to the tip. I've never had one actually fail in flight, but I check them afterwards and bend the prop. If it is fatigued it will just break, where a new one won't.
I've used the 8/5 Sport prop on the Nelson 36 for quite some time. They never broke, although after 10-12 flights I'd usually throw them away anyway.