I smoked for about 30 years and I quit smoking cold turkey in 1993. After three days, my wife noted the "rattling" had gone from my chest while I was sleeping. I could also take a deep breath with no pain nor coughing. I thought of smoking for a while and even liked being around people smoking as it smelled good. After a couple of months, people smoking really irritated my sinuses. Now, if anyone smokes, I can smell the pungent odor of their breath and clothing across the room.
I swore I would never harass anyone who smokes and I still abide by that today. There's enough information available about smoking without my adding any warnings.
I will encourage anyone to stop smoking that wants and can guarantee only one thing: "It won't be easy but it'll be worth it!"