Mold or smoke/residue damage from an unreported fire/meth lab etc..

The residual income comes from the monthly fee the deadbeats are supposed to pay.

I know I can get there; the question is, do I want to work as long as necessary to get there or would I rather enjoy financial freedom earlier with a smaller residual income.

One might say that the inherent risk is lower, although the mitigating factors are also lower, and it's difficult to identify the magnitude of the "residual risk," knowing that the Fed can't drop in with lower rates like before.

It depends on the subfloor.If I have clean concrete (not too much adhesive, paint etc) I do stained concrete (acid first then marbleize with acrylic)If I have concrete which cannot be stained I tile.

Like you said at least I can start small and get some residual income flowing.

We used a Drylok paint on the walls then uses steel studs and Roxul insulation in the basement to further protect the building from any residual moisture. 

Mainly the smell of pee/ammonia but also residual poop smell.  

Also, please make sure you use a modified polymer thinset mortar and not a wall tile adhesive.

Mold Control leaves a residue that prevents mold from regrowing.