(Battery operated electronics in water tank = bad idea).  

I also wrapped in some basic analytics like rental days/goal days, average booked rental rate, average rented days, etc.And I included some very simple reminders to let me know when to change air filters, smoke detector batteries, things like that.I couldn't rely on syncing Airbnb and VRBO/Homeaway calendars using the tools that either company provided so I just rolled my own. 

We inspect our units every 6 months, change smoke and carbon monoxide batteries and HVAC filters, and Thermostat batteries.

If you think the above strategy smoked your calculator, now figure that one out, make sure you have fresh batteries. :)I may also know what the odds are as to obtaining a DIL, most are willing to avoid foreclosure, most will walk with a small chunk of equity to walk.

The cost to re-tenant and recondition that unit is likely substantial and will take along time to make back.When you can't verify things as a buyer the price starts dropping and dropping.

Usually most people would replace a battery every 12 months but in reality most alarms tell you when they need a new battery by beeping- Personally I don't want to be notified if they leave for 3 days

Our office will generally offer a lease termination for 2 months rent (ample time to recondition, market, and lease the property.)

Mechanical keypad locks are available for your gate I would think, they are push button and do not need a battery. 

Repairs needed at the time: battery for the smoke detector.

I little rush and a dead battery but looks decent.