I mean managing the move ins and outs and screening and service animals and smokers and parties and and. 

Previous owners were heavy in house smokers - we took a $2000 deposit for removing the smell but it ended up costing a lot more than that.

I'll tell you a bit about where my 4-unit is located and what I deal with:-Located across the street from a bar (a neighborhood bar - nothing too rowdy) so there are beer bottles and cigarette butts on my curbside grass fairly regularly-My credit score requirement is 625 for C-class.

The side of the evicted tenant was pretty bad and they were heavy smokers so we had to pretty much remodel the entire side with new flooring, paint, and appliances. 

The tenants seem like good people but are all heavy smokers (stair case reeks cigarette smell), they are also using the attic for storage (I have no access) and occupying the majority of the side lot for parking.

Even if marijuana is legal in your state, you should have a policy against smoking indoors and a "right to quiet enjoyment" clause that essentially tells them to be good neighbors.I would give the smokers a written warning that their smoking is bothering the neighbors.

As a pointer and as i had to learn the hard way too, i now require a extra security deposit if the tenants are identifying themselves as smokers, similar to a pet deposit. i make it refundable so if there is no damage upon move out they can get it back. 

Allow them to smoke wherever they can smoke cigarettes.

Think it through ahead of time how you want to deal with pets, smokers, satellite dishes, pest control, small repairs, large repairs, early termination, lawn care, ETC. 

As far as the health affects/ smell/ damage to the property,  it is a different product than cigarette tobacco, and is unlikely to linger or create any damaging issues once the upstairs tenant is removed.