Power of attorney is a legal document that lets one person — the "agent" — act on behalf of another person — the "principal" — for financial, legal, or medical matters the principal specifies. Both people generally need to be adults of sound mind when the document is created. * The scope of authority is entirely customizable, which is why POA isn't one single thing but a category with several distinct types. A limited (or special) power of attorney grants authority for a specific, narrow task — selling a particular property, or managing one account while the principal is traveling — and nothing beyond that. A general power of attorney grants much broader authority, covering banking, contracts, and property management across the board. * The distinction that matters most in estate planning is durability. A standard, non-durable power of attorney automatically ends the moment the principal becomes incapacitated — which defeats the purpose for a lot of people, since incapacity is exactly when this kind of authority is often needed most. A durable power of attorney is specifically built to survive that moment: it remains fully valid even after the principal can no longer make decisions themselves, which is why it's one of the most commonly recommended estate planning tools. * A springing power of attorney adds a condition on top: instead of being active from the moment it's signed, it stays dormant until a specific triggering event occurs, most often a doctor's determination that the principal has become incapacitated — meaning the agent has no authority at all until that condition is formally met. * Whichever type is used, a power of attorney automatically ends at the principal's death — at that point, the agent's authority stops entirely, and whoever's named executor in the principal's will takes over instead.