We see it in our family on my spouses side.
Great grandmother lived to 101, wore a housecoat everyday and cleaned the house daily, swept the pathways, smoked until 96 then gave up.
Her son, now aged 86, still works 2-3 days a week as a general labourer, still has a six-pack of sorts, non-smoker, two drinks in the evening.
His daughter, 53, extremely fit, no illnesses ever. Non-smoker, two drinks in the evening.
Grandson, 22, extremely fit, non-smoker. Hardly drinks, no vices.
Common similarities, not shared by wider family members on both sides -
All look physically similar (willowy) compared to the rest of the wider family (this proves the gene theory).
Only interested in modest food portions, just not 'foodies'.
Always doing something to keep busy.
Only ever had colds, nothing worse.
Not ambitious.
Laid back, avoid confrontation.
Low blood pressure.
You just know that, bar the proverbial bus, the daughter and grandson will live to 100 or so.