We also do our own maintenance/turnovers when we can as we've found they charge a lot for labor, so things like re-screening windows, changing smoke alarm batteries, light fixtures, etc., can be ridiculously expensive if you let them do it. 

Have house alarm and lock I control remotely..fyi..

Read a lot your library will have a lot of these:Rich Dad, secrets of the millionaire mind, set for life by Scott trench, 10x by Cardone, the psychology of selling by Tracy, smash your alarm clock by Jason Buzi.

So I grabbed a baseball bat and ran over to the house, but the thief was gone by the time I got there (and had already managed to steal some more wiring). 

I would recommend to use the Ring Alarm system. 

This should send up red flags and alarm bells to any investor.

Both the Broker and the employing broker need to be aware of state and local laws that impact the performance of property management duties, which include, but are not limited to, laws pertaining to security deposits, habitability, carbon monoxide alarms, asbestos, lead-based paint, handling of confidential information, zoning and agency."

Do commercial landlords have keys and alarm codes to all of their tenant spaces?

Humidity will set off a alarm.

I just saw a commercial for the Ring Flood Light with Motion Activated Camera, Alarm, Speaker, etc...