The only "emergencies" I jump to are when the AC goes out and it is 105 degrees outside.Typically if it is a water leak flooding the house situation I would very much like to know as it can cause a large amount of damage.

Now, you go in and make sure the plumbing, electrical and HVAC works, you make sure there are no roof leaks or floor damage, etc.

Even if the Freon is leaking (which is very expensive), replacing that is WAY cheaper than replacing an entire system.

The cast-iron manufactured starting in the early 1970's has a life expectancy of 15 to 20 years and we get a tremendous about of leaks in the newer cast-iron in less than 5 years.

What if without permits, the smoke/CO detectors were not installed properly or in the proper locations, or electrical or plumbing work were shoddy causing a fire or plumbing leak and mold and tenant health issues, etc.

I envision someday portability of the work location...Tonight I hosted a Zoom call from my car at my daughters soccer practice with my iPhone setup as a WiFi hot spot.

There is a slow leak under the sink, which seems to be coming from the supply line. 

When the water heater began leaking I contacted the Home Warranty company as required by them to receive covered service. 

If a septic for sewage make sure you get a die test to check for leaks.  

Of course, any empty houses during this pandemic will have only zero readings  unless there is some leak ...