While I've heard similar second hand (probably 100th hand) information, I can tell you my own experience. Last car I owned for 18 years. Ran the AC probably 5 hours every other year. I own a home with a 25 year old air conditioner. Typically use it about 15 hours total in the summer. Only lived in the home 12 years. Those are my real anecdotes. Heard the same thing about dishwashers. And other appliances. Cannot remember any appliance ever dying. Even my electric toothbrush is 12 years old (I do use it every day though so maybe you are right). Personally, I think these are old wives tales from men.Yes, but what I've been told is that it's good to run your AC periodically in order to keep the seals from drying out and cracking and losing all of the refrigerant gas. There is a lubricant mixed with the refrigerant and running the AC causes that to circulate. The last guy who inspected my home AC system mentioned that I should try to run it a few times over the winter for this same reason.