But I'd still posit it's harder to drive a tangible, measurable, ROI to offset the investment.

If the landlord must enter as an emergency measure, they can enter without notice."

They are competitive in price and offer more services than the big boxes, since they will handle the measuring and installation.

Cut out a piece from the 1/4'' back panel that will slide into the refr door (Usually the refr will come with instructions and all of the measurements are in the installation instructions)2.

I recently had a flooring contractor ask me for more than 14 -16 boxes of vinyl flooring and I bought it like he asked; however, once it was delivered and the work completed at the property, I made sure to measure the area the flooring had been placed and got 2 quotes from 2 flooring stores.

Its a measure of good vs bad investment.However, in the case of the author where he lives in 1 of the units, I'm not sure sure you should consider counting the 12K income.  

@Javar Hargrave what I’ve been taught is to take a tape measure and pen and paper with you when you go look at a house.

It seems like more and more areas that are high traffic (vacation destinations) are putting measures in place to discourage or stop short term rentals (Airbnb type or <30 day rentals). 

Example:Heat is measured in BTU'sElectric baseboard or space heaters $35.13 / per 1,000,000 BTU'sNatural Gas                   $10.02 / per 1,000,000 BTU'sHeat Pump                    $14 / per 1,000,000 BTU'sIt is 3.5 times as much multiplied by every month you are paying to heat the property.Here is a free calculator offered on the Department of Energy's website:http://www.eia.gov/tools/faqs/heatcalc.xlsI just wanted to make you aware of your options and any necessary information before taking on that monthly expense.Also, with a central system, you control it (WiFi Stat).

Granted, this component can be mitigated to a point by bringing in an experienced partner or by using a reputable PM, but the point is a bank can, and will, see the big picture.You NEED to have your own funds into the deal for this to have a measurable chance of success.