When I got my first car the seller was a smoker.

I rented to some tenants in September that are chain smokers.

The question about her, her relatives and friends smoking she answered "All non smokers"  And that was a lie too because her mother smelled like a dirty ashtray and had cigarettes in her pocket when she brought over the rent. 

One of the applicants qualifies in every way (clean background check, good credit score, non-smoker, etc) except that she has no income.

i owned a 4 unit once in st. albans and would not recommend it unless you know your stuff , its a different animal , different market . i was less than a 1/2 mile from the hospital and couldn't find the people i wanted ( made them pretty nice ) i think everyone was a smoker and in and out of a job .

The previous tenants were inside smokers and vacated the place leaving it trashed. 

I have telephone screened a few and weeded out some who have pets and others who are smokers. 

looking at a BRRRR opportunity where previous owners were smokers inside the house for 15 years.

You are NEVER going to prevent smokers from smoking in your non-smoking property.

Nate, I have been down this road with long term smoker tenants that have moved on.