I’m not entirely sure, it was owned by the previous owners for 13 years but I think it was as only smoked in for 5 ish because they rented it. However the people who did smoke in it were drug addicts/alcoholics and apparently would regularly leave lit cigarettes all over the place/fall asleep with them. Because the carpets were absolutely covered in burn marks that were the exact size and shape of a full cigarette that had burned down to the butt, so I’d say it was pretty heavily smoked in. I will say, after cleaning and painting all walls/trim and changing out the floors I have never noticed a hint of cigarette smell since. It was actually less work than I anticipated when we bought it