Which ABMS Member Boards issue time-limited certificates, and where do I find more information about when time-limited certificates were first issued?
All 24 ABMS Member Boards now issue time-limited certificates of varying lengths, depending on the board. Physicians who were certified before the initiation of these time-limited certificates have been grandfathered and do not have to seek medical board recertification, although many physicians choose to recertify even if they have lifetime certification. This is why you may see subsequent medical board certifications after an initial lifetime certificate. Some boards also offer limited medical board recertification for shorter periods of time to help fulfill physician CME requirements, resulting in overlapping dates. To find out when each board began offering time-limited certifications, please consult Time-Limited Table: General Certificates and Time-Limited Table: Subspecialty Certificates.
http://www.certifacts.org/timelimited.html#1