I would only show an occupied unit if it looked better than an empty unit (nice furniture, clean tenants).

Just came into a duplex to fix a leak due to a moldy exhaust pipe for the AC.

This cannot happen when it is hot and humid, which leads to increased risk for heat stress and exhaustion.

LOL.Or, they come home exhausted with kids wanting to know what's for dinner, and there's your notice on the door telling them that after they make dinner, do homework, put the kids to bed, they will now be up until 1am cleaning the house. 

Now I am wondering about the exhaust above the stove though. and The floor is concrete. 

They mainly look for doors and windows that function and lock properly, appliances that work, that bath exhaust fans work (if no window) that you have functioning smoke and carbon monoxide detectors and secure railings if more than 3 stairs.There is more paperwork.  

How exhausting.  

Install a low-decibel exhaust system either in the common area or in his particular apartment, or encourage the other residents to move on if he's just signed a long-term lease.

The exhaust vent only has value when it is actually turned on.  

A good management company has connections with travel agents and larger travel sites that can drive better leads than an owner alone so in the end it all works out.