are the air filters being replaced? 

I'm an Air Force veteran (POL! 

That said, neither of us want a long-term renter in our house; we feel odd about someone calling it "home", but we don't mind the prospect of doing an Air-bnb or the like. 

This can still work out ok, but it's a tough road and I think you can likely find even better opportunities.Is the home located in a viable Air BnB area?

Keep the utilities on, mow the lawn, change the air filter, replace burned out bulbs, test the smoke detectors and replace batteries, shovel snow, rake leaves, haul off trash, etc.For things that may require a special tool or knowledge, I ask them to submit a work order and let us take care of it.

I have a vendor who changes air filters every quarter, and we get HVAC cleaned once a year, dryer vents, little things that don’t cost a lot but help prevent bigger expenses.

I can understand ignoring the kids to make sure you air on the side of caution but where should the breaking point be? 

As it's a townhome, and the HOA covers most big-ticket items except water heater and air conditioning, would it be necessary to still budget out $100-$150 for both repairs and capex each month?

Tankless water heater (2016), central air system (2017), Furnace (2018), New windows installed (2018).

Tankless water heater (2016), central air system (2017), Furnace (2018), New windows installed (2018).