This leads me to two conclusions:
The majority of certification credentials now include some kind of explicit or implied maintenance activity.
The number of programs with no maintenance requirements continues to decline (at least a dozen programs that now appear in the "None or N/A" column should move into the time- or version-specific columns within the next six months).
Clearly, the notion that certification is an ongoing process rather than a one-shot effort is an idea gaining credibility in the marketplace, and one that's already attained critical mass. I can't help but endorse this concept, in the face of ever-changing details, features, and functions in the items on the IT landscape, not to mention the relentless pace of technology changes and new introductions.