I started smoking as a teenager, smoked almost every night from age 16 to 24 or so. After that I stopped enjoying getting high. It made me think too much and over analyze all my actions. I would do it once in a blue moon but would have years where I didn't smoke at all. I'm close to 40 years old now and started to smoke again this year.
For me the perfect balance is about 2 times a week. Its enough to maintain some sort of a tolerance so that you don't get completely retarded from a few puffs, and not too much that you become dependent and cant fall a sleep without it.
Since starting to smoke again, I have not touched alcohol in over 6 months. Not one sip, so that is one HUGE benefit for me. The only downside that I notice is that it may have had a negative impact on my temper, I have been easier to anger. I am not 100% sure that it is related, but its possible.