I was up to three pack a day when I quit in '93. The Dr who ran the smoking cessation class said that the body would purge all the toxins and restore itself to it's original condition, of course I didn't believe him. Several years later I had a chest x-ray during a physical and we studied that x-ray and discussed it for a bit. I couldn't see anything abnormal and the Dr said there was no evidence at all that I had ever been a smoker. But, if I die of any kind of cancer, even at 100, I'm sure we'll blame my smoking for my death.
I'm not so sure it works for all like that. Am sure a lot of people who smoke for say 10-20 years when younger feel the effects of breathing problems in their 60's or so due to smoking when age 20-40 years old.
Either way, I applaud all those who use to smoke and have quit, good for you all! Congrats.
I wish the lady I worked with for near 10 years would quit smoking she smokes enough and is now age 50 who knows into her 60's what it will do to her? Then again, could be like George Burns and fine up until age 90 or so?