@Drew Denham  The same things as a newer property, plus lead paint, asbestos, underground oil tanks, poor or no insulation, old plumbing including possible lead drain pipes, copper pipes with lead solder, those are a few of the worst and most common.

We had a duplex which we desperately wanted to refi, but due to the tanking economy (thank you 2008), we got a lender, locked, got buy off / appraisal passed muster by the hair of my chinny chin chin. 

At the end of the day I purchased 5 houses, 3 more than my intended 2, I flipped 2, "wholetailed" one, converting 1 to a triplex with 3 storage units, and am looking into subdividing the last parcel into 3 parcels, selling 2 and then lease-optioning the house after remodel.

They even had a 'shark tank' just like the TV show.  

Arrange Inspections for City Sewer/Septic Tank Systems 27.

We had often talked about retirement strategies and land investments, and since her father rents out storage units we looked into that as well. 

Free rent is something that is standard in certain types of real estate deals, I am buying a self storage facility where the current owner is occupying 6 of the units.

Once the market tanked the reality of being able to survive in this industry became unpromising.

The place was fully renovated back in the 1990's, and all the hot water tanks were installed in the basement - so each unit has an independent hot water run.  

If you pick a house on the wrong block, don't make connections with the neighbors, don't take out the faces of the cabinets and the hot water tank then you are in real risk.