I got a biopunk nation with widespread life extension procedures. There's a unique phenomenon after someone undertakes this procedure: they get locked into a specific, 'age' appearance unconnected to their age when they took the life extension. So you get a situation of a 100 year old looking like she's 20 after the procedure while a 20 year old looks like she's in her 50s.

It's not a matter of procedure quality as even the most privileged, which has access to the best doctors, are still afflicted by the same problem of mismatched actual age and superficial appearance. From a story perspective, this is my visual metaphor for traditional and progressive immortals. From an in-universe perspective, why does this phenomenon happen?

Policy. The stance of the government at the time it was introduced was that wisdom should be valued over youth, the regulatory body that controls the tech ensures it. @Dmyt

(That goes for the appearance of wisdom too I guess.)