When it comes to ageing, you need to pick your battles. Most of the time this means that you need to get your skin microbes to fight your battles for you. If your immune system has to respond to every tiny threat by calling a full red alert, your ageing rate will be high. Your troops will crack under the stress and burn out. Probiotics allow you to deploy millions of minions to take out the vast majority of the daily incursions that the microbial world throws at us.