They are just quick & dirty ways of doing cocktail napkin math on properties. 50% rule - The costs to operate a rental property typically averages out to 50% of the gross rents on an annual basis. . . .One question that comes up often on BiggerPockets threads is the net profit (free cashflow) per door.Some say $100 per door minimum or no deal.

Guys, this one misses the mark on my goal of $200 per door, barely, and I'm missing the cash on cash ROI with this house as well. 

@Brandon PellmannI’m buying another 50 units in KS MO instead. 10 cash on cash 20% IRR per year.Already own 26 doors going to 75+Staying w what I know

"Driving the area" using Google Maps I would rank investing there as the same risk profile as investing say New Kensington, Brackenridge, Aliquippa, etc.I am not sure of the economic drivers in that area, on the bright side it's NOT in a flood zone :)

I could simply frame a door opening between the 2 units if I wanted.I suspect in your case you would take your best guess at which local building department has jurisdiction. 

Remote locks, security, intelligent door bells, Alexa etc. 

Interiors of the homes are unknown (fire department boarded up the doors and windows to each home).

When 200 bills come through the door, manually calculating these out makes me feel like there's got to be someone out there smarter than me who's figured this out haha

I have knocked on her door, though no sign of anyone inside room for about 4 days now. 

@Ashish AcharyaGive me a shout post 4/15.Right now I generally get on BP in-between clients to de-stress a little.Not a good time to get into a debate and dive into code sections.Perhaps my most recent example was too hasty reviewing the regs right now...The "-3" reg defines structural components by reference to Treas Reg Sec 1.48-1.The term “structural components” includes such parts of a building as walls, partitions, floors, and ceilings, as well as any permanent coverings therefor such as paneling or tiling; windows and doors; all components (whether in, on, or adjacent to the building) of a central air conditioning or heating system, including motors, compressors, pipes and ducts; plumbing and plumbing fixtures, such as sinks and bathtubs; electric wiring and lighting fixtures; chimneys; stairs, escalators, and elevators, including all components thereof; sprinkler systems; fire escapes; and other components relating to the operation or maintenance of a building.We know that a building and building structures are a single unit of property.