What percentage do you use for Cap Ex Expenses for recently rehabbed single family

[Sigmund VanDamme]

I am trying to sharpen the pencil in regards to my financial model for the single family homes that we own.  We currently use 3% but I am finding that is inadequate and I am wondering if anyone here had a back of the napkin number they use.  I am sure it varies depending on the property and features like age of roof and appliances, etc.

Any guidance much appreciated.

Thanks,

-Sig