Personally, I conceptualize longevity as consisting of two components:
Delaying the onset of chronic diseases and accidents.
Building a life worth living
Cancer and atherosclerosis are examples of chronic diseases, while falling and car crashes are examples of accidents. I first learned about this aspect from Peter Attia.
A sense of purpose, social support, and freedom from pain/suffering are all elements of a life worth living. I first learned of this aspect from Marsha Linehan.
These two figures are my primary influences.
I do not view longevity to be an optimization problem. Occasionally, the language of optimization can be useful. Other times, it’s dangerous.