Nobody likes to consider the worst that could happen, but we need to be prepared. If you were in an accident, how would paramedics know to notify your family? How would they know your medical history? Where would they get information vital to your care? The answer is already sitting next to you: your phone. There’s a feature called “Medical ID,” and it could be the key to saving your life one day. David A. Cox shows us how to set it up.