It uses batteries, but I have never changed them yet.However, for this rental property, I am concerned about battery life, as I may not be around to replace it if one stops working and a guest comes. 

Something with rechargeable batteries works well usually.

In the eastern area of Cleveland - not the nicest but around university circle they have nice places. i invested closed to battery park, behind edgewater Beach but you have to be careful here you Walk 1-2 blocks and you go from like B to C-D pretty quick. let me know if you need further help.. 

My wife has a Mustang that has sat so long in the garage, I've put 2 brand new batteries in it and both have gone dead from the alarm draining them.

Consider changing your garage door opener code as a security precaution.Service your lawn mower and yard equipment (blowers, edgers and trimmers).Clean your faucet aerators and inspect your plumbing for leaks.Clean and sharpen your garbage disposal by running a tray of ice cubes and depositing a cleaning (foaming) product into the disposal.Inspect or have tested your home fire extinguishers.Replace smoke alarm batteries.

The Simplisafe system works on a cellular platform with a battery backup of 8?

They passed a battery of tests to be certified.Paul

I've had tenants take light bulbs and smoke alarm batteries before, but never anything like you just experienced. 

At a minimum, our clients pay to have the locks changed, change smoke detector batteries, provide some furnace filters, and do a light clean to the property.

(i.e. quarterly furnace filters, smoke detector batteries, light bulbs, etc.)Thanks!