Yeah, 500 flushes is not really very many. I live alone and I reckon I flush the loo at least three times a day, which would mean the coating needed reapplying

Yeah, 500 flushes is not really very many. I live alone and I reckon I flush the loo at least three times a day, which would mean the coating needed reapplying every six months. If you're a family then it's probably heading down towards every three months. If this spray can be re-applied by the end-user and isn't too expensive that's annoying but just about OK I guess. If it needs a technician visit and/or it's an expensive coating then it's not practical. An order of magnitude more flushes between recoatings would definitely be better...