Depending on the contractor, I will sometimes just take myself out of the equation and provide the contractor with the tenant's contact info and request they contact him/her directly to schedule the repair visit. 

I suspect once you add those numbers into the equation you're break-even at best, negative at worst.

Paying down the mortgage only makes cash flow worse...you have a big cash outflow day 1 that can not be excluded from the equation.

Take the guesswork out of the equation.

I have put in some CAPEX/Renovation dollars into the property, would that also go into the COC equation?

Besides- my wife is the only one who picks up the landline... 95% garbage calls.I self manage and I have found that the more that I engage myself, the less that a contact will annoy me- It is just part of the equation (they are few and far between).

@John CarboneYou have a few things right:Investing internationally adds a specific sets of risks to the equation.

That's not "millions per minute" but rather equate to 400-500 a minute (in a heavily contaminated environment).  

There is more to this than can be quantified with a math equation.

For those of you that don't know, the basic accounting equation is this:Assets - Liabilities = Owner's EquityWe're all in the real estate game for Owner's Equity.