As @Steve Babiak points out: cheap enough for the tenant to buy themselves, and too finicky for you to maintain.

It made more sense for us to self-insure by maintaining adequate vacancy reserves.  

The one weak point with GNUCash is the ability to export into commercial accounting systems {without me having to maintain a utility to convert the GnuCash file into an input stream my accountant could manage}.

But it only costs $800/yr to maintain that $7200 which is still a positive $6400.

Only one heater to maintain might be a plus although boilers cost a lot more to replace.I hope to view the property in the next day or two.I am aware that I will need a commercial loan due to the five units.Pete M.

While technically the owner of the property if to maintain the deposit(in most states), many Property Managers have been burned by lawsuits when the owner fails to account for the deposit upon move out or more often foreclosures. 

I have a much larger commercial line of credit currently in process and all I had to send was a personal balance sheet (which I maintain each month), latest tax return, property P&Ls (which took me five minutes to run from Xero), and a rent roll from the property manager.  

It's hard to say where the smart lock journey is going but the company that stays flexible and evolves to create the most compatible (door- and lock-types), easy to install, maintain and use solution, will be around in years to come.

These types of agreements often sound good in theory but in reality are often counterproductive to maintaining a home in good condition. 

and you maintain it?