Smoker TTC

Soooo I just wanted to open this to others who may be in the same boat. I'm 28 and TTC with my first. I also happen to be a smoker. Granted, it's less than half a pack a day, but I'm not an idiot, I know that's still not good. For some of you others in the same boat, did you quit before or after you got pregnant? Like, I know I should probably quit now for health benefits and all that. But I feel like finding out I was pregnant would be the best motivation, as I've smoked for 17 years (I know, that's pretty bad.) So, was finding out a big motivator for anyone? Did it work? Was the stress of quitting bad during pregnancy?