What wear out on pellet stoves? they said don't run it on 5/5 for more than 2 hours,...

they said don't run it on 5/5 for more than 2 hours, why is that? Granted it's kicking out 200 degree nouns (last time I checked metal doesn't melt anywhere close to that), the auger is running twice as swift and the blower is on high. what would effect this to wear out faster (as they explained in the manual)? and except the fan and auger motors, what else would wear out?
Answers:    I would bet the auger will wear out the soonest. If you run it at 5/5 for severely long you will probably go broke anyway and not be capable of afford pellets so nought will get worn out. (they're $4.40 a purse where i live)
thats it, running it efficient will wear it out, metal to metal, pellets rubbing on auger, close to any thing else it will wear out,
worked surrounded by a grain plant, corn will wear thru 1/4 inch steel within a month, [at high speed]