Can an ex-smoker live healthy to an old age?

Yes: Statistically speaking, both non-smokers and ex smokers are likely to live to a healthier old-age than smokers. Of course there are exceptions to every rule. George burns lived to be 100. He smoked 18 cigars a day and drank. At 92 he was asked what his doctors had to say about his lifestyle. "what can they say? They are all dead!".

Hopefully.: Although it may not affect every individual this way, it's felt that each cigarette you smoke in your lifetime reduces your life expectancy by seven minutes. Do the math.