As a result, I didn't include a separate CapEx expenditure as my belief is the $4,673 maintenance/repair item would act as a method of capturing CapEx, capital reserve building going forward, and turnover costs.

NOI does not  include debt service (loan repayment) nor should it include capital expenditures.

Single family home in need of some TLC for sale in western PA for $39,900.Median house price in the neighborhood $75-80kAverage rent for a similar property in that zip code $850-$900I would be putting down 20%, 5% interest, 30 years.Allocating $15k for rehabTotal cash needed $24,177Rent: $900/moVacancy: 5% ($45)Taxes: $238/moHome Insurance: $38/moMaintenance: 8% ($72)Capital Expenditures: 8% ($72)Utilities/Landscaping paid by tenant. 

You also have the advantage of doing all your cap ex (capital expenditures) up front.

We purchase and rehab everything and fix it to the 9's to avoid unexpected capital expenditures.

@Wave TaylorI purchased a turnkey 3 family home 10+ years back in a C+ area and even though most of the improvements had been done, there were still a few capital expenditures that had to be handled within the first 7 years.

That to me includes all the furnishings, the original price of unit, expenditures, etc. 

I realized, I dont have a method for tracking my expenditures.

This more than covers the mortgage and gives us some cash flow for expenditures annually. 

@Ahmed Sublaban I think a simple template will do that shows the annual estimated rent less the following: (economic vacancy at 5% of rent, annual tax, annual insurance, annual property management at 10% of rent, annual estimated mortgage amount, and 10% of rent for capital expenditures and repairs).