I don't know how long it took her, but my great-aunt quit smoking at 80. She's lived to 93 so far, and her doctor says that her lungs have healed themselves to a remarkable degree. I mention this because I've known people who hit a big birthday ending in 0 or 5 and decided that there was no longer a point. Onie doesn't wheeze any more. She goes out and clears the ice off her own walk, though we wish she wouldn't.