One-pack-a-day smoking habit will cost you at least 2 teeth every 10 years.
According to 30-year studies at Tufts University, chain smokers lost an average of 2.9 teeth after 10 years of smoking one pack a day. Non-smokers lost an average of 1.3 teeth after 10 years. A smoker that quit will reduce his or her toothloss to 1.7 teeth. (Source)