Most people can expect to live to 90-95 years if they follow healthy lifestyle

(1) https://pubmed.ncbi.nlm.nih.gov/29712712/ In USA, men with 5 healthy factors lived 87.6 years (men without healthy factors lived 75.5 years).
Women with 5 healthy factors lived 93.1 years (women without healthy factors lived 79 years).
The 5 health factors were very easy: (1) no smoking (2) moderate alcohol (3) BMI 18.5 -- 24.9 (4) >30min/day physical activity (5) top 40% diet quality
All of that can be easily achieved by anyone. More strong adherence to healthy lifestyle would lead to even longer expected lifespan.

(2) https://pubmed.ncbi.nlm.nih.gov/31915124/
Men who followed 3 elementary and 2 slightly more complicated rules of healthy lifestyle lived an average of 91 years (of which 82 were cancer/serious heart disease/diabetes free). Though, these were not ordinary men: 58% were dentists, 20% veterinarians, 8% pharmacists, 7% opticians, 4% osteopaths, 3% orthopedists, all from the US.
https://sites.sph.harvard.edu/hpfs/about-the-study/

Their 3 elementary rules of a healthy lifestyle:
- never smoke.
- have a BMI of 18.5 - 24.9
- Every day at least a half an hour of brisk walking / similar activity.
1 more complicated rule of healthy lifestyle:
- Drink an average of 5 to 30 grams of ethanol per day (that's about 60 to 380 ml of 10% wine a day)
Probably if you drink less it would be good as well, but authors didn't count that as healthy factor.
- Be in the top 40% on the AHEI Healthy Eating Index

(3) https://pubmed.ncbi.nlm.nih.gov/31750895/ Chinese living in Singapore
Six healthy factors: (a) BMI 18.5 to 21.4 (up to 24.4 for >65 years), (b) never smoking, (c) >0 to 14 drinks/week (for women half as many), (d) >2 hours moderate activity/week, (e) AHEI top40%, (f) sleep 6-8 h
Men with 5/6 health factors who lived to age 50 could expect to live 87.8 years (women 89.8), suppl.fig.7
Following such simple rules! What if they actually took care of their health seriously?
(btw, men with an average score of 2.73 who lived to age 50 could expect to live ~83 years (women at 87.3))