What is Refresh rate for your banners and how did you calculate the optimal value?

What is Refresh rate for your banners and how did you calculate the optimal value? Lets say you have an app with average 60 secound session duration, what would be the optimal refresh rate for this app. Is there any guide for refresh rate calculation?

I’ve experimented a lot with mine and I’ve never increased or decreased my effective revenues from the traffic.
That doesn’t mean you won’t though, of course.
It naturally going to depend on the type of app as to what interval you set.