My company is well staffed now but when we were starting out I frequently hosted many properties while traveling. 

I would be checking the air filters on the furnace on your routine visits and encouraging frequent changing.

If you do something like an RV that has that on site you have to fill up the water frequently and drain the sewage.

FWIW I leave the power off in Tahoe frequently and pipes don't freeze.

The lock I am currently using at one of my properties dies very frequently and I’m trying to avoid the same situation on a new property.

Here in the desert we frequently see heatpumps, but there is a furnace for "emergency heat. "  Not sure what the normal lifespan is, but the one in our residence is gettting pretty ricketty at 20 years old, and the heat pump just went down.  

We also live in California which is traditionally more litigious than other states, less landlord friendly and known for changing the rules (on everything...) frequently. 

I've been wholesaling in chicago for a number of years and I frequently wholesale in in the Bronzeville neighborhood.

Couple that with the fact that wildfires and earthquakes are becoming more frequent and the fact that the cost of housing has not responded at all to all of those issues and you can see why so many are eager to leave.

(Fun fact, my wife is Canadian and we go there frequently.)