Taking care of the health basics - a good physician, exercise, diet, and supplementation - in a steady, reliable way makes a real difference in the long term. It is probably possibly to swing the end of your life twenty years one way or another at today's level of medical technology. That is just the result of choices you make and resulting changes in health and level of biochemical damage sustained over the years - no magic involved.

Here's a study offered as one more piece of evidence for the benefits of keeping on top of commonplace health matters:

Following up on growing evidence that higher levels of conscientiousness are associated with greater health protection, the authors conducted a meta-analysis of the association between conscientiousness-related traits and longevity.

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Using a random-effects analysis model, the authors statistically combined 20 independent samples. In addition, the authors used fixed-effects analyses to examine specific facets of conscientiousness and study characteristics as potential moderators of this relationship.

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Higher levels of conscientiousness were significantly and positively related to longevity. ... Associations were strongest for the achievement (persistent, industrious) and order (organized, disciplined) facets of conscientiousness. ... Results strongly support the importance of conscientiousness-related traits to health across the life span.

If you let things go, the consequences will come back and bite you in years to come, cutting your life short and increasing your chances of missing out on the development of real, working rejuvenation medicine.