General or Durable
A general power of attorney often has broad and sweeping powers that allow an attorney-in-fact to perform practically every action and sign most any document the principal could have signed if personally present. This type of power of attorney usually has "durable" language, stating that even if the principal later becomes mentally incompetent, its powers remain in full force and effect. Unless a general power of attorney has a specific expiration date, or the principal revokes it in writing, or an event occurs that terminates it under the law, it should remain in effect until the death of the principal.
Specific or Limited
A specific or limited power of attorney is limited by its terms. It may be limited to a specific transaction, such as signing a deed or mortgage and other documents in a real estate transaction. It may be specific to signing medical or release-of-liability forms for recreational activities when a friend’s child is on vacation with you. A specific power of attorney terminates when the specific action for which it is intended has been performed. A power of attorney may also be for a limited time, such as when a person is out of the country. A limited power of attorney of this type may give an expiration date, after which time its powers are no longer valid.
With any type of power of attorney, the powers granted terminate upon revocation. There may, however, be language in the power of attorney or specific state law that holds persons or institutions harmless, or not liable, when they act in good faith on a power of attorney if they received no notice of its revocation. A revocation of a power of attorney should be in writing and signed by the principal and provided to the principal’s financial institutions or other parties with whom he transacts business.
If the attorney-in-fact withdraws, dies or becomes unable to otherwise act under the powers given in the document and there is no successor attorney-in-fact named, the power of attorney will terminate. To prevent an unintended termination, a power of attorney should name a successor attorney-in-fact to act in such event.