Why do people put Teflon tape around the tap thread in caravan parks? They don't do it at home! I thought everyone knew that the thread only holds the hose to the tap. It's the face of the tap, perfectly flat and smooth, that creates a seal against the rubber in the hose nut. If you don't have a good rubber you don't get a good seal - and everybody knows where that leads.

Among the many little spares I carry, most of all I carry many spare rubbers. (Not the sort you are thinking - I saw a man with a sharp knife many years ago)