No tenant has ever forgotten or discounted a landlord who calls them up in mid-December to take $100 off next month's rent.One of the best reasons to have regular battery-power smoke detectors and carbon monoxide detectors in your rentals is that they give you an excuse to enter and do a casual inspection when you replace those batteries twice a year.

@Owen MitchellIf you buy on ebay I'd try to make sure that the batteries are still good and not too old. 

Just had to take off the front panel and it looked like a battery that just needed to be unplugged and replaced.

During the prepurchase inspection I noticed the battery low message on the thermostat.

Duplex is in Battery Park.

Can Simplisafe or another system run off battery? 

Make sure it's in good working order; smoke detectors have batteries, doors have working locks, fire extinguishers in place. 

Make sure the tenant changes the filter often.Landlord vs Tenant ResponsibilitiesYou're onlyresponsibility is to provide a safe, habitable property that is up to codeSmoke detectors,heat, appliances, plumbing are things you are responsible for If a tenant breaks something like a window, hire someone to fix it and charge the tenant Tenants responsibility to report problems or they will have to pay for itAnnual Preventative MaintenanceSpot problems beforethey become an issueGive the followinglist to a handyman once a year (interior): Change furnace filters Vacuum dust from fridge coils Replace smoke detector batteries Check carbon monoxide detector is working Sweep fireplace Ensure lint from the dryer vent has a clear path to outside Flush water heater Check the expiration date on fire extinguisher Repair broken caulk or grout in the bathroom Tighten any handles, knobs, racks etc.

Our cleaning crew does all the normal STR stuff--cleaning, restocking, laundry, replace towels, reset beds, and will do the occasional odd job like replacing batteries.

When I got there there were no batteries in the thermostat, and the heat wasn’t turned on.