Many people draft wills to dispose of their property after they die, but many people do not plan for the possibility of becoming incompetent. Using a power of attorney can allow someone else, known as an agent, to manage your finances or health care if you cannot communicate yourself. This can be very beneficial because you can provide your agent with specific instructions and limitations to help ensure that he or she acts according to your wishes. In addition, failing to plan for incapacity can cost your family substantial amounts of money to appoint a guardian to oversee your business. The guardian may not necessarily act according to your best interests if he or she is unfamiliar with your goals and values.

Source