I believe the idea was lint build up as cleaning it out may be just as hard as replacing it in some cases? I know I check our outside outlet to make sure it is clear, but I will admit I haven't checked the hose itself. It isn't a long run in my case, about 5-6ft I'd say.I've never heard that.... did they provide any kind of reasoning for replacing it? It most certainly should be checked/cleaned to ensure there isn't a buildup of lint blocking it, but I don't know about replacing it.