You can use changing smoke detector batteries or changing furnace filters as the reason to enter the property.

Make sure the image clearly communicates or perhaps choose another one.As some others have noted, the tone is dark and heavy which isn't as consumer-friendly as it could be. 

How would I be able to have a good estimate vs a stab in the dark at estimating repair costs?

If you purchase a building that's greater than 5 units and less than 10 and it isn't in a smoking good area, I would probably not look at it.

Treated for bugs, replaced the interior and exterior "Zinsco" Breaker and service panels ($10,500), remodeled 2 bathrooms, replaced 3 of 5 water heaters, smoke detectors, added kitchen and bathroom GFCIs, 1 AC unit, 1 new dryer, replaced 2 windows, repaired several more windows.

I t was very dark inside and needed a lot of electrical updates and TLC What was the outcome?

Samsung smart things hub with WiFi smoke detectors and a smart lock. 

I like a dark brown that kind of looks like dirt, if you have the tile to pull it off, because after a year of greasy, dirty feet and shoes it will be the color of dirt even if you seal it. 

Right now I think there is too much smoke on the water to make any kind of meaningful projections.We have COVID, and the possibility of a worldwide recession (unrelated to the covid) looming out there.I think America will weather these problems much better than other countries, but as far as comparing one area to another right now, I think there are too many variables //risk//. 

I can smell their smoke from my living room, dining room, and bathroom.