@Angela DeBorja while none of these things are a guarantee a property is vacant, I look for:tall grass and unkempt landscapingflyers stuck in door when no other houses have them, free newspapers piled upPhone book on doorstep when no other houses have oneBoarded upbroken  Windows.

Aqara camera and sensors, circle view doorbell camera & indoor camera, plus eufy cameras outdoorsCurrently tying my stuff via HomeKit 

Also to clean on a regular basis.In Washington State, at the time the lease is signed, the landlord must provide the tenant with information provided or approved by the department of health about the health hazards associated with exposure to indoor mold.

I've heard of indoor pigs getting anxious when they're alone and they can chew on the walls or try to tear up the flooring. 

Heating costs go up in winter, as does electric due to the reduced natural light and people being indoors more.

You cannot tell them to take children to a public swimming pool, have them run at the park, get them outside to play but we all know that when children have healthy exercise they don't go wild indoors, they read a book or grandmother reads to them...If the downstairs tenant works from home this can be bad for them and create stress.I like the idea of offering them to switch units but the upstairs tenants aren't going to want to do the neighbor downstairs a favor.

And it was indoors.

Two swimming pools, an indoor gym, a dog park, and more).

They have a great area around the new Diamond Knot Brewery with a dog park nearby, and an indoor public pool with racquetball courts and kids activities.

@Robin Searle is that $60 indoor or outdoor?