I smoke because I like it. I'm gradually switching to "vaping" (first I vaped, then I smoked again, now back to "vaping"). I don't like it when binge drinkers look down on me for smoking, lol. I'm a non-drinking smoker, which is apparently not "cool" or something. I dunno.
I can't speak for other people, but I try to eat fruit and vegetables and I take tons of antioxidants (Orthomolecular--may or may not be part of the reason for my level of health these days...) that, based on limited data (thank you, PubMed) may help reduce some of the ill effects of smoking and..well...life in general (stress, meds, etc.).
I think all smokers who cannot/will not quit should try some supplements. Clearly, I'm not a doctor, but it makes sense to try to put back, in high doses, what smoking depletes from your body. I think of it as Harm Reduction. With Harm Reduction, I'm personally going a step further and switching to vaping, until such a time as I can drop nicotine all together.
Anyway...that's my rant on smoking.