A living will records your wishes about medical treatment for a situation you hope never arrives: one where you are alive but unable to communicate. It speaks to questions like whether you would want mechanical ventilation, artificial nutrition and hydration, or resuscitation if your condition were judged irreversible. Despite the name it has nothing to do with property — it is a healthcare document that happens to share a word with the instrument that distributes your estate.
Its real function is to remove an impossible decision from the people who love you. Families asked to choose whether to continue life support without knowing what the patient wanted often carry that choice for years, and relatives who disagree can end up in genuine conflict at a hospital bedside. A living will replaces guessing with instruction.
It works best paired with a healthcare proxy. The living will states your preferences; the proxy names a person empowered to interpret them when a real clinical situation does not match anything you anticipated. Medicine produces more scenarios than any document can enumerate, so naming a decision-maker matters as much as writing preferences down.
A living will is only useful if it can be found. One filed in a drawer at home is of no help at two in the morning in an emergency department. Give copies to your physician and your named proxy, and keep a copy somewhere your family can retrieve on short notice.