Just an idea popped up in dreams:

the main conception I personally have is that bad habits for health (no sleep, eating too much, no enough exercise...) cause little micro-damage to the body and the sum of them in the long run is the manifestation of aging. More aging, more damage, more probability to death. Law of thermodinamics so you cant reverse process/preserve in a perfect way, so you will age and then die.

Ok, but there's more, here comes my idea.

What about the asymmetry of of aging-die? aging happens everytime, death happens 1 time (in most cases), aging happens slowly, death is a matter of seconds, aging is delicate, death is violent.

The point is: aging is just a part of death. It represent how you can resist without die in case of violent episodes.

In particular: aging is like having a little healt remaining in health-bar of a video game. It is slowly decreasing (because of aging) but if some enemy attacks you (a violent episode for the health) you will die.

Imagine a hearth stroke. You have aged, you are fragile and full of damages. But today you eat too much pizza (+ a lot of peculiarity that makes this day "the day": you sleeped bad, you eat bad in this mount, you have too much stressed, it was really a bad pizza....). This violent episode cause a stroke. You die.

Maybe you could have been alive for the next years if today you opted for a little portion of good meat.

Ok, if we accept that what I sayd have some sense:

what is the role of "bad habits" in predicting the probability of death? Today we focus too much on the "aging" side, but not on the "death side". I never heard noone say "if you eat bad, at least do it when you feel good so to avoid the stroke".

Death is violent and I think that a great reason why you need to have good habits is to avoid statistically to have a death caused by "a bad day" where you do bad things for your health; not just because of the "more aging".