My grandfather smoked packs of cigs/day from his 11th when he started working his parents fields. My mother never saw him without a sigaretten in his mouth. Died obese and still smoking at 96 suddenly (no known health issues). Seems a lot longer, but of course he wouldn't. And a lot less happy I think: the guy never stopped smiling and cracking jokes and singing; he liked his drink, smoke and a lot of food; if he would have to let those go, I think it would've made him very different. Will never know of course.