I am 71 and have been smoking pipes and cigars (never cigarets) off and on since I was in my early 20s. I currently smoke at least 3 bowls a day. It has not adversely affected my health in any way. Stained teeth and bad breath are cosmetic not health problems. My wife worries that I'll develop oral cancer and she's not wrong to worry about that. (Saves me worrying about it I guess.) Putting a carcinogen like smoke in your mouth must logically increase the risk of oral cancer (how much it increases the risk is harder to measure). The thing about oral cancers is that they can be diagnosed fairly easily. If you see your dentist regularly and ask her to check for changes to your mucosa you can likely catch cancerous changes early. Dentists are supposed to do this anyway but aren't always systematic in doing so. The treatment for oral cancer, however, is not pleasant. Inhaling cigaret smoke, and by extension pipe smoke, does increase the risk of lung cancer, heart disease, etc. and those maladies are harder to diagnose. For me the take-away is don't inhale and see your dentist twice a year.