I used to smoke a pack a day a while back (15 years ago?). I was trying to be an athlete at the same time, and found my cardio to be suffering, so I quit, and never missed it. I'd cough a lot when I did heavy cardio.
I'm 47 days sober, but alcohol was literally part of my diet for decades, so it's harder. Fridays and Saturdays are tough, but I'm dry somehow. I'm turning my plans into mental ques.