A durable power of attorney is one that either takes effect upon or lasts after the principal's incapacitation. This is different from a general power of attorney, which would terminate at this point.
According to Section 751.00201 of the Texas Estates Code, a person is considered to be "incapacitated" for the purposes of a durable power of attorney if a doctor's examination finds that they are not able to manage their own finances. The doctor must provide a written statement certifying this finding of incapacity.
Texas's statutory form of durable power of attorney is found in Section 752.051 of the Texas Estates Code. It is a financial durable power of attorney - this means that it only allows the agent to handle financial matters. It does not permit the agent to make decisions about the principal's health care.
Section 751.131 of the Texas Estates Code states that a durable power of attorney lasts until:
If a spouse was appointed as the agent and the couple divorces or the marriage is annulled or declared void, Section 751.132 of the Texas Estates Code states that their authority as agent terminates.
A durable power of attorney is generally used to make plans for the care of your finances, property, and investments in the event that you can no longer handle your financial affairs yourself.