On Microsoft Recertification Policy
One obvious question for those of you who invested loads of blood, sweat, tears, time, and money in earning your Microsoft certification is, "When will my credential expire?" Let's address that question today. In the past, it was always somewhat fuzzy to me in knowing (approximately or precisely) when Microsoft would announce the retirement of a Microsoft Certified Professional exam or credential. What I have taught my students historically is that you are normally safe for one revision of the technology under consideration. In other words, if you had earned your Microsoft Certified Systems Engineer (MCSE) title on Windows 2000 Server, then you were safe until Microsoft develops two versions past this one.
More on this at InformIT.com.