He either leaves it on Heat or Cool but doesn't understand how to change temp. 

CapEx - You say no HVAC, there must be some sore of heat system and that will get old at some point. 

Building costs continue to rise, thus re-sale market continues to heat up.

The bidding wars are pretty heated for dialed in houses that are intentionally under price... 

The "newest" property I have ever acquired was built in 1961.Things to look out for, but are all fairly obvious during inspection: type of wiring, boiler vs forced air heat/air, foundation issues, tuck pointing on a brick property, sewer line scope (particularly if trees are near front of property).  

It also has a finished basement, finished sub-basement, above ground pool with a deck built around it, and a 50x30 outbuilding that has heating, A/C, and a half bath.

I have never paid a contractor in draws for jobs under $10k except as mentioned - my HVAC guy, for example, I know is a small one/two man operator and so I will pay him 50% on the front end so he can order and pay for heat pumps and materials.

I'd love to buy a distressed duplex in my market, but multi-family is over heated and difficult to find.

Lots of old houses well built and completely upgraded on electrics, windows heating systems etc. and I'd pay more attention to that than the actual age.

No central heating, windows units, kitchens and exterior/yard all renovated.