Cap-Ex per Unit, per year by Class

[James Dickens]

When running numbers on a property what cost numbers do you use as a rule of thumb for Cap-Ex per unit, per year, by Class?

I know this could be nitpicked to death with a lot of other factors such as year built, Roof Type, Heading and AC type, which is great if you want to add that information as well. However, I just wanted to get a feel for rule of thumb type numbers if you would like to share. 

Thanks!