I don't smoke and I won't smoke. It's a matter of principle for me.
Ganymed is basically right, you shouldn't make promises. I myself have almost relapsed many times. Although I've never tried smoking, watching others, I subconsciously developed the idea that smoking relieves stress. That's why I feel the urge to smoke a cigarette in stressful situations, but I resist. And now I've found an alternative to smoking - chocolate. I eat some kind of Twix, Mars, or a bar of Alyonka almost every day. And also during stressful times. Of course, money also goes away, but at least chocolate is not just harmless, but also beneficial.
As for alcohol, I drink, but mostly on holidays, mainly red wine; the exception is drinking with friends, where there is only vodka, but such drinking sessions happen once a year, rarely twice, no more often. And I don't drink beer at all.
I haven't tried drugs and I don't advise others to - it's really evil, it's better to smoke.

