Okay, so we have McCoy still puttering around at the age of 137, which FYI is 13 years longer than the longest confirmed lifespan in real life of Jeanne Calment who lived to be 122. (No other human has reached 120).
Dr. Soong apparently wasn't quite that old when he died, but seemed to be pretty active as a guy over a hundred. Keiko's mother and Beverly's grandmother both lived to be a hundred. Dr. April Wade live to be 106.
The fact that McCoy's and all these centenarians out there doing stuff leads me to suspect there are probably humans even older than him. (Dax once O'Brien dying around 140, but she wasn't being too serious).
So short of being in suspended animation, or kept young by some sentient cloud that's in love with you, or something like that, how long do you think the average human lifespan is in the 24th Century?