SFR Deal Analysis - Vacancy & Maintenance Rate Assumptions

[Brendan Illies]

Hello, 

I'm a data-guy so I'm building my own deal analysis workbook. One thing that I've seen is a rather simplistic assumption regarding Vacancy and Maintenance rates as a percentage of gross income - typically 3-5%. I was wondering if anyone has some background on why these values are realistic expense assumptions. 

Feel free to add any other SFR operating expense assumptions that I should account for (i.e. not insurance, property taxes, PM company).

Thanks in advance.