Seems like this will unlock some serious leverage for me.

And it unlocks VA for #3. 

When she left, said to me "I'll be back".Had I had ring installed back then, I wouldn't have bothered to answer the door despite the incessant rings as she didn't look right.Then I have kids forever forgetting to lock the front gate in front of the front door, persons unknown trying unlocked doors don't ring the doorbell, came barging into my house, when I confront them, says "sorry, guess I'm in the wrong house".

Probably a better chance of getting someone who will leave doors unlocked, thermostat on cold, lights on, rent it out themselves, or better yet move in. 

It seems like we did have one unlock a door for us one time and then he left and asked us to lock up when we were done. 

Now they don't have a key or code to unlock the doorknob. 

Can also lock/unlock with the press of button and see if the door is open/closed/locked/unlocked.

Have you considered a cash-out refi to unlock equity in your current property and use it to secure a DSCR loan or a fix and flip loan (if repairs are needed) on your next property? 

You are interested in economical.Instead, perhaps take an intermediate/advanced Excel course to unlock a lot of what Excel can do.

One of my tenants once caught an ex-tenant's ex-husband trying to unlock her door.