We have not changed our minds about the validity of the passport. In our opinion, it should be valid for five years, for reasons related to security. It is much easier to integrate new technology as soon as it becomes available. It is also easier to update the document itself by changing its security components. And it makes it easier for border service officers to recognize the document. If a passport were good for 10 years, an officer would have to memorize all of the various iterations that have occurred during the past 10-year period.
On June 20th, 2007. See this statement in context.