Smoking for 40 years that would be 5 months at 1 a day or 17 years at 40 a day.

I think that's all consistent with what you said: 2 packs a day and you usually, but by no means always, don't make it to retirement at ~66. Five months is enough that I'd take some care to avoid it, though.

[0] https://pmc.ncbi.nlm.nih.gov/articles/PMC1117323/

[1] https://www.theguardian.com/society/2024/dec/30/single-cigar...

to some degree that is exactly the thing

by smoking you add a risk

and the more ways you add risk through your live the more likely you will die an early death

it's just basic statistics

and for the same reason you will find someone who does add all the risks but somehow still dies with 90+, if your sample size is large enough and factors complicated enough you are pretty much guaranteed to find some pretty big outliers

but realistically speaking it a pretty bad idea to assume you are such an outlier, but many people tend to ("basically") do exactly that (due to an combination of subconsciously avoiding reality and simply not thinking things through)