If you aim for less nice neighborhoods, your cap rate and C of C will be much higher but may not be worth the headache.

Materials can be a black hole so putting control measures on them in your contract is imperative.

@Justin HerringtonDid you measure the bedroom windows in that lower unit?  

The cash-flow, and more specifically the cash-on-cash return and total ROI is the best measure. 

I usually invest in single family homes, so I'm not sure what type of cash flow I should be aiming for on a duplex. 

@Lourdemir Aime Financing comes in different packages, with each package having a different use.  

If someone (here) reaches out for knowledge or spouts (perceived) flawed knowledge, who wouldn't want to respond in a way that is aimed at steering the ship in the right direction, as soon as possible?

Colleen, you mentioned the bill ($) is up, but I'd want to dig into the actual consumption of electricity as measured by kilowatt-hours, this year versus last.  

You don't want to be annoying but you want them to "think" of you when they decide they want to swell.That being said, this isn't the best time for them to sell for tax reasons unless they are thinking about 1031 or another tax measure

Thirdly your reputation will proceed you, and eventually if you treat people with respect, and ethically, then I believe you will be "Blessed with the measure you use to bless others" Best of luck.