The purpose of a living will is to guide your representatives and doctors when they’re making decision about end-of-life medical treatment on your behalf.

The living will typically states the specific type of health care you do and don’t want near the end of your life. Living wills usually only take effect when your doctor certifies two things: that you’re incapacitated and that you’re nearing end of life.

A living will is most useful when you have filled out a health care proxy form that appoints an agent to make health care decisions on your behalf when you can no longer make them yourself. The living will can guide your agent in making decisions about your treatment and care, and reassure them that they’re making the decisions you would want.

A living will tends to express in general terms what kind of treatment you do and don’t want. For example, it might say whether you would want treatment that would artificially prolong your life. Some people list specific kinds of treatment they would accept or reject, such as artificial hydration or nutrition (a feeding tube), dialysis or chemotherapy. If you write a living will, make your preferences as clear and specific as you can.

If you don’t have a health care proxy—or if your agent can’t perform their duties—your living will can still serve as a guide for your physicians. A living will can also solve disputes among family members and other caregivers about whether you would or would not want life-sustaining treatments.

You don’t need a lawyer to write a living will, but you may want to consult one. This is especially true if you have unusual requests or if you foresee that there will be disagreements between family members. You can use a standardized form and tailor it to your individual needs, but make sure it meets your state’s legal requirements. Discuss it with your health care agent, loved ones, and providers. Give a copy of the document to your health care agent and providers.