I think of a persona as a specific (yet generalized) instance of a role to "personify" and represent what users that play that role, might be like. While we originally argued over the details of the personas, a great by-product was that we focused on the distinctions across our various customer sets. This helped reduce ambiguity during product design. It also helped us make calls on where to put our resources and effort.
My recent road trip was a great reminder how quality is durable. As I passed through familiar territory, it was interesting to see how many building and places stood the test of time.