I've found that for myself, most treats wind up daily habits. I suspect any tobacco use would eventually go from once/year to once/month to once/day to who knows what. Probably because I used to smoke cigs, and the nicotene jolt from that is pretty heady stuff.
But I don't think my sinuses would take any amount any more; and the guilt (of thinking the health impact) is too much for me to bear. I'm not getting any younger. So I have no plans to touch the stuff ever again. Even though I wouldn't mind a pipe, it's just too much of a risk. Plus, I've got young impressionable kids, my wife is allergic to it, and odds are pretty good I'll lose a brother to the stuff if he doesn't quit.
Oddly enough, being around smokers, or stale smoke really doesn't bother me. My grandparents, who did die from smoking, were chimneys; and so for some perverse reason the smell reminds me of them. And not in a negative light. Dunno why. It's hard to get away from the fact that tobacco was a major vice for most of the last century.