If you are in Davidson County, you either have to build them on land that is zoned for mobile home use (and they would need to be mobile - not permanent foundations), or you'd have to build them as an accessory dwellings to an already existing structure (i.e., on land with a dwelling already that is zoned for multiple dwellings).I talked to codes about this because I wanted to build one on my lot (.25 acre with a SFR on it) but the zoning is RS10.

You want to make sure your zoning allows an accessory unit and/or a two-family dwelling first. the fist link is the zoning map and the second is the zoning code.

Hello, I am closing on a home with a an attached accessory unit.

If it is zoned for a duplex or AUD (Accessory  Dwelling Unit, i.e. mother-in-law unit) You will have to get Permits and bring it up to todays codes.  

My current situation:Stay at a friends property in an Accessory Dwelling Unit.Rent free.No primary residence SingleLow personal monthly bills.My question is, from strictly a financial perspective, would it make more sense to stay where I am or look for a primary residence as part of maybe a fix and flip?

One thing to check though is see what the house is zone for or if the allow an accessory dwelling unit if your going to use it as a duplex  or multifamily. 

NH is passing a new law next year, in June of 2017, making it legal to rent accessory apartments in your home to people other than family members.

We're planning to add an accessory dwelling unit (ADU) to the existing duplex by merging the two parcels together. 

I'm in the process now of looking into Accessory dwelling units to maximize the duplex and still occupy. 

Also, owners have nice vehicles and spend extra on them like new chrome rims, fully tinted windows, and other dumb accessory stuff.