Bunk.

Here's one common chart Source:

20 minutes:
Blood pressure drops to normal
Pulse rate drops to normal
Heart rate drops to normal
Circulation has already improved
Body temperature of hands and feet increase to normal
8 hours:

Cigarette breath disappears
Carbon monoxide blood level drops to normal
Oxygen blood level increases to normal
Is already feeling better and it's only been 8 hours
24 hours:

Chances of heart attack begin to decrease
48 hours:

Nerve endings in nose and mouth begin to regrow
Ability to smell and taste are enhanced
Mucus begins to clear from the lungs
2 weeks to 3 months:

Circulation improves
Walking becomes easier
Lung function increases up to as much as 30%
1 month to 9 months:

Coughing, sinus congestion, fatigue, and shortness of breath all decrease
Lung cilia have regrown, increasing the ability to "clean" lungs and reducing the likelihood of infection
Overall energy increases
1 year:

Excess risk of coronary heart disease is half that of a smoker's
5 years:

Lung cancer death rate decreases by half
10 years:

Lung cancer death rate is now equivalent to that of a non-smoker
Pre-cancerous cells are replaced by healthy cells
Risk of other cancers (mouth, throat, bladder, etc) decreases
15 years:

You are at now no more at risk of heart disease than if you had never smoked!

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I can't find an article about the research which I saw on the news, and googling is giving me 20 different answers, so I'll just base it on this and say "at worst, 10 years" and leave it at that. Either way, its sure as #### not 5 years for every year...that's utter tripe.