Sales Specialist (Partner-only cert) is valid for 2 years. Technical certs are valid for 3 years. For ACMA and ACMP, you simply retake the current version of the exam. For ACMX and ACDX we are working on a written recertification exam that will be ready the second half of 2012. If your cert has or will expire in that time (ie it is 3 or more years since you passed), you will have 6 months after the release of the recert exam to pass, after which your cert will expire.