Simple things like a branded email at your domain and a website can open a lot of doors. 

I can't see how some investors cashflow just $100 per door in some markets. 

Non-tangible property includes buildings, land or other inherently permanent structures.I get a lot of questions on which group specific assets belong in, so I put together a list to help.Non-Tangible PropertyBuilding (27.5 or 39 Year Useful Life)Land (Non-Depreciable)Paved Parking Areas (15 Year useful life)Swimming Pools (15 Year useful life)Fences (15 year useful life)Bridges (15 year useful life)Exterior Landscaping (15 year useful life)Docks (15 year useful life)Sidewalks (15 year useful life)Tangible Personal PropertyMillwork or decorative trimCarpetAir Conditioning equipmentShelving, cabinets and display racksAccordion doors and partitionsWall coveringsInterior landscapingNeon or other signsDecorative and business specific activity light fixturesGenerators, machinery and kitchen equipmentWindow treatmentsWhat other questions do you have regarding cost segregation?

Without an HOA, and with more doors, you'll likely see a higher monthly cash flow.

I would warn you though as soon as you give an inch, the next month if rent is not paid on time you may have opened up a door of forgiveness that was not intentional.

I own 12-doors in Detroit and 3 of those are rented to section 8 tenants.The best areas for S8 tend to be C Class neighborhoods.

It tends to hide marks better.Walls: Neutral tones like SW Repose Gray, Behr Swiss Coffee, or Moore Classic Gray are renter-friendly and modern.Trim and Doors: Use a crisp white like SW Extra White or Moore Chantilly Lace.Accent Walls: For a touch of style, consider an accent wall in soft blue-gray. 

Getting the foot in the door with a primary residence is a great way to start.

There are markets that have built in "gotchas" like the rising cost of insurance in coastal FL, regulations in much of the west coast states and property taxes in Texas; however, the deal itself is the most critical factor.

Compliance items such as adding smoke detectors, hand rails, fire resistant garage entry-door and new stairs outside.