For as long as the property is owned by the purchaser, and up to the purchase price or value on that property. The one time premium paid is optional - either at the time of purchase or at a later date. Nevertheless, an Owner's Title Insurance Policy provides a lifetime of protection to that specific owner against title defects that could otherwise affect that purchaser's claim to the parcel of property.
A Lender's Policy protects the interest of the lender up to the value of the loan issued and is typically always required. A new policy must be issued for every new loan issued on a piece of property. The one time premium is paid at the time of the closing, and concludes once the loan is paid off.