For example, weighing the option to keep your single family, or tear it down and build a 6 unit.

@Claudia Lewis I'd probably consider 1 and 3 to be normal wear and tear.

STL as a whole has been on a tear the last couple of years. 

on your first post, regarding the MH that is a tear-down, probably indicatesthat it's septic may be needing major work or replacement up to new codes,may be just as costly or perhaps more than new, with environmental disposalissues, etc.

I plan on tearing out the drywall.

I have an opportunity to purchase this property, and tear it down to construct a 4 or 5 level condo type building (which is what is being done by the local developers in this area).

Those are my ranges for recent full tear-offs with deck replacementYou'll get lucky with some stuff in that it'll last much longer than normal. 

The lease would have a provision that says the tenant is responsible for any repairs not caused by normal wear and tear.

It has been proven to me over many years that is a dark and dangerous road.In our leases, it states that if the maintenance issue (lets use clogged toilet or sewer main) is a result of normal wear/tear or lack of owner maintenance, the charge rightfully belongs to the owner.However, if the tech pulls out a toothbrush or Barney the Dinosaur out of the drain, the full charge belongs to the tenant. 

That only banks really cared about operational agreements and we could tear up and submit other versions later.