I would try the cameras.

Make sure the inspector has a thermal camera which can detect hidden moisture inside walls. 

That would be critical for any type of rental--MUST have a 2nd means of egress or face potential liability in case of bad stuff happening.If you DO have exterior access, and you can get it property secured, maybe also add a wireless video camera.  

Now we want to insert a camera into you lungs to photograph them.

Get it camera/scope inspected all the way to the sewer.

Things like a month long trip to Australia and New Zealand, a few expensive camera gadgets that I want, etc.

My pictures are more than ten years old taken with a basic point and click digital camera.

This happens all the time and nothing tells the truth more than a recording.Every time you set foot on 'your rental', put your cell phone in your front shirt or jacket pocket facing the the camera out and turn on the video.

Lol the camera guys were not happy about the smells they were exposed to that day, lol.

I should have been more specific in that the technology in the cameras, screens, interface, etc has reached a point where there is very little room left for innovation.