If you're the sole breadwinner, you need to be concerned about income stability. If you're like most people, you only think about unemployment when considering income stability. But, medical conditions can lead to loss of income stability as well. Unfortunately, if a medical condition isn't caused by an on-the-job event, you could find yourself without any source of income, especially if you haven't done any advanced planning. That's where long-term disability insurance comes into the picture.