Once a power of attorney has been completed and signed, it is valid and can be used. The power of attorney does not have to be stamped or registered anywhere. It is only necessary to deposit a power of attorney to deal with land (at the Lands Titles Office) or shares (with the company's share register). However, some financial institutions (banks or credit unions) may want to record the fact that a person has appointed an attorney or may request to have a copy of the power of attorney document - without this, it can sometimes be difficult for the attorney to be able to exercise their powers.

A power of attorney may be created for a certain period of time only, or can continue to operate until the death of the donor. In general, a power of attorney operates from the date on which it was signed [Powers of Attorney and Agency Act 1984 (SA) s 5].

A general power of attorney can simply state a commencement and ending date.

It is possible to delay the time when an enduring power of attorney is to come into effect by the use of careful wording. For example, the official 'Enduring Power of Attorney' form gives an option as to when the enduring power of attorney will become operational by stating:

This form is to become effective:

Choosing the second option means the form will not be effective until the person becomes legally incapacitated. However, deciding when someone becomes legally incapacitated can be a complex legal question.