That means, by necessity, they MUST do really high volumes, throw as much spaghetti at the wall as possible, see what sticks.In that context, I would not at all be shocked if they were just guessing. 

Refinance, supplemental loan, etc. should be a BONUS, not a a necessity.

The functional necessity of having a car that will start every single time you turn that key, guaranteed, which is the reason most people have always stated is why they drive almost new cars and pay their car payment, has been largely removed from our society.

Vacation rental insurance is a necessity, since sooner or later you'll have to deal with the aftermath of a less-than-ideal guest.7) Aren't water, sewer, and electric metered separately by the condo association, and therefore payable by the tenants themselves?

@Nettles Mason admittedly this is not my forte and a bit outside my personal skillset, however my immediate reaction was "Necessity is the mother of invention". 

They do it out of necessity to make some money to survive in between getting the commissions from selling houses.What would the average person want to do?

You need to look at your balance sheet and decrease your expenses, what seems like necessities might be a luxury in the world of achieving cash flow.

Closing costs and necessity to start paying the loan back right away without having an immediate use for it.

If it wasn't a calc error, is meeting the cap rate an absolute necessity before going for a deal?

I chose one of the lowest-risk ways, to turn myself from a teacher and a reasonably good handyman-by-necessity into a good renovation handyman, an expert on my target area, and a capable low-income landlord.