I've never had an impeller fail,i change it yearly though, keep the old one for a spare, had one where the pin had worked its way out a bit, I fitted new pump because it wouldn't prime itself after impeller change, had a fair bit of wear in housing, put some rubber grease in and it would seal good enough to start pumping , then it was OK, but it was original 2007 pump, so fitted a new one to be safe