I used to smoke when I was a teenager between 12 and 16. Up to 2 packets/day of "Gauloises" (French brand, brown tobacco, no filter) by the end.
Then I began to think that my time doing laps in the pool sucked. So I stopped drastically. No cigs at all. And I got better.
On the evening of my 20th birthday, I was wishing for a smoke. And I thought : To hell with that, I'll be twenty only once, go for a cigar.
I cannot say that I'm addicted to cigar, but I indulge once in a while (8 or 10 times a year) and they're big (Churchill size).
As for the booze, I had a few episodes as a youth where I went on a binge session. Now, I'm out of that. I still indulge, but I drink a lot less and a lot more better. From Jhonn y Walker Red (2 bottles/night every week end) to Balvenie Cuban Wood, my current favorite (half a glass every 2 or 3 weeks).
On the drug front, never did it. And I never had that desire. Unless you consider girls as a drug