The iPhone allows the ability to use old headphones if you use an adapter. So you have to remember to carry that with you. You then have to buy another adapter to charge the phone at the same time as using the headphones. Say you want to use YouTube, but not pay for Red, Unlimited, or whatever they call it now. You have to leave the screen on, which means eating the battery. Two dongles or you run the risk of running your phone down.