That margin is way too small for meAlways include a property management fee in the numbers even if you are not using one because one day you may need to; you still want the numbers to work I use 5% vac rate, 7% repair, 10% capital expenditures, 10% property management feesWhen I analyze properties my minimum is 10% CoC ROI - if it is not 10% then I see why... i.e. is it not managed properly, are the rents too low for the area etcYour inspection cost is way too high - it will run about 600 for inspection and radon testMy mortgage guys gets me a loan for 20% downI hope that helps a bit.

I use 10% capital expenditure rates to help budget for future costs. 

However, when the major capital expenditures hit, it will bring me much closer back to the 50%. 

I personally always account for all expenditures, including vacancy when calculating pro-forma numbers.

I deduct 10% of the monthly rent for capital expenditures(initially this includes repairs and durable items), 10% for property management and 10% for vacancy. 

Do not look at a full rehabbed unit and think that the cap expenses are small because there are not any near term cap expenditures expected.  

This will mean a monthly cash-flow for me of $800 for my eight houses.Now here is my question: Since the turnkey properties are newly rehabbed with all big ticket items (old roof, old water heater, etc.) taken care of for a while, one could argue that I will have only very few capital expenditures during the first few years, and will only need the capex reserve IF I hold the property long-term (say 7+ years).

Other than the roof, what is the estimated life of the other major capital expenditures (CAPEX) you'll need to complete [HVAC, water heaters/boilers, appliances etc]?

Capital expenditures should not be confused with your routine maintenance / repair cost but rather an expense simply related to things wearing out and needed replacement.

What would be a good method to determine what a properties expected capex expenditures would be when analyzing properties for consideration?