We see the Car there everyday and night and the new person brought me last months rent.On top of that we are now smelling Cigarette smoke through the walls since they ”moved in.”What should I do?

We've come up with some alternative solutions like they clean out all their personal items from the basement and garage in a short time period as well as stop smoking inside (heavy heavy smokers).

If the units are reasonably clean and in good condition and there aren't piles of stuff/junk everywhere and the place doesn't smell like mold, weed or cigarettes its a good sign.  

In the upper unit, the tenant has lived there for a number of years and smokes inside the unit - it's definitely going to need some work to address the cigarette smoke/tar build up. 

A few of the units around me dropped their prices, but even then they wound up renting to people that I rejected due to any number of reasons, so the season has definitely thinned the pool of good prospects.My units show well and are all updated, but I have fairly high criteria (650+ credit, non smoker, 3x rent) so it may also be a factor.

In Calif with a licensed MFU 5+, the fire marshal requires working CO+Smoke detectors and annually replaced extinguishers.In 2013 a cigarette lit the couch on fire and we suffered $95k damages. 

As long as you are not furnishing the rental, cigarette smoke remediation is not hard to get rid of.  

Looking to get a place rent ready but was previously lived in by a heavy smoker. 

There's really no greater risk of a fire with a normal indoor smoker vs the one with the tenant on oxygen in it.Now if you want to go with a no smoking policy then do it, but I wouldn't justify it (to yourself let alone them) that you're in some way making things safer/better.

We figure if someone puts a cigarette out into the floor, it just looks like another knot.. haha Ask me how I know!!