Large properties and estimating expenses and Capex

[Jeff Prather]

I have an opportunity on a Quad in a very desirable neighborhood of Nashville, TN. The asking price is $600,000 and rents are $6,000. 

A question for investors who have experience in more expensive properties with higher rents

When I use typical expense and capex estimates of say 5% of rents each, I feel they are overstating annual expenses due to the large dollar value of rents. Does anyone agree that $3,600 each for repairs and capex annually sound like a lot? I mean, 72k in total for both in 10 years??? Is there an alternate method for more expensive properties with high rents?