Despite sharing the word "will," these two documents serve almost entirely unrelated purposes — one is about medical care while you're still alive, the other only matters after you've died. * A living will is a medical directive. It spells out what kind of care you want — or specifically don't want — if you become seriously ill or incapacitated and can't communicate your own wishes. Common decisions covered include whether you want life-sustaining treatment, feeding tubes, or breathing machines used to keep you alive in a condition with no realistic recovery. It only comes into play while you're alive but unable to speak for yourself; the moment you die, a living will has no further legal function. * A last will and testament is entirely about what happens after death: how your property and assets get distributed, who's named to manage that process as executor, and who becomes guardian for any minor children. It has zero authority over medical decisions and doesn't take effect until you've died — while you're alive, it does nothing at all. * Because the two documents cover completely different situations with no overlap, having only one leaves a real gap. A last will alone provides no guidance if you're incapacitated but still alive — doctors and family would be left guessing, or fighting over what you would have wanted. A living will alone says nothing about who inherits your house or bank accounts. * That's why most estate planning guidance recommends having both, alongside a closely related document — a healthcare power of attorney — which names a specific person to make medical decisions on your behalf in situations your living will doesn't explicitly address.