If you have zero vacancies, zero tenant damage, make sure utilities (especially heat) stay on every winter even if the tenant doesn’t pay.  

.: Quote from @Brandon Brown: I am considering switching to a heat pump with an electric heat strip for supplemental heating in our two-flat building, with plans to add a third unit in the future.

Nothing spells trouble more than one unit having the heating/AC controls for BOTH units.This property is in Denver County.

Otherwise contract a service for the season that will automatically take care of for every snowfall.4) YES you need to heat them!

I needed $35,000 for a new heating system so the bank gave me $28,000 (80%) in a business loan for 60 months which has no prepayment penalty.

And if you do not think you will get caught, a lot of nosey neighbors will call you out on it (we did not rent a basement but we had built a shed as an outdoor dog house that was heated and air conditioned and someone called about that on us...).

Updates of heating, adding cooling, and electrical.

We have also completed some exciting improvements including retyring a boiler for heat/cool ductless mini-splits and 9 units being electrically updates.

And heat and cool can only be turned on by them, with their phone. 

Alhtough values continue to appreciate, home prices are coming down as competition gets heated with more homes on the market.