Immediately when you walked in the front door the smell hit you.

And good lighting is important.Many basements have high humidity so it's better to stay away from carpet and go with vinyl plank or another flooring that won't get moldy or musty smelling. 

Generally speaking our property smells clean between guests, just due to cleaning product.

@Kai Kopsch yep it’s all about that energy you emit, if it’s trying to get something from someone they smell that a mile away!

Without, it will be an uphill battle. 

Addiction is a very difficult struggle and I admire anyone who fights that battle.

We had to use 3 coats of Kilz to neutralize the smoke smell, replaced all the carpet, new granite in the kitchen and bath, new appliances and flooring, new fixtures and switches/plugs, and a little drywall work.

There is no distance requirement or certain number of days you must utilize the property for your personal use but it has to pass the smell test in underwriting. 

Both attics are pretty "clean", except there is evidence of a squirrel (crap) in my tenants attic, BUT no smell of anything dead, AND no swarms of flies in the attics.

The inside of the house had a musky smell.