The house hadn't been on the market long. 

For me it’s building connections with buyers in a new market. 

So, the extra unit may cost you more then it brings if you cannot access equity or if the market discounts the property when you go to sell due to financing available.

I used a heloc to purchase the first 4 rentals, so $155k of dept is wrapped up In  that until I refinance each property which have already appreciated extremely quickly given the current market. 

I am in the Memphis Market as well. 

Agent and leasing experience can help with negotiation skills, market knowledge, and tenant screening.

The Cville market is quite competitive.

I am seeing a trend in CA that ADU construction is more cost effective (per unit) than buying on the market by a long shot.

We manage several hundred rental properties throughout the San Diego market and I found your post very interesting. 

I suspect maybe something like Hagerstown or Cumberland, which yeah are Class D like markets with declining populations, high drug problems, no strong job base which leads to non paying tenants.