How much ads is too much?

Every app/website owner that relies on Ads to monetize wishes to fill up the entire page with ads to become rich in two days.

The question is are there some well known frameworks or studies that guide through best practices for amount of ads that can be placed before the user destroys the heck out of the machine?

Please keep in mind, i am not looking for answers like "research it, or benchmark it", i'm trying to find somewhat a golden rule of thumb for cases where resources lack to conduct such activities, even if it comes slightly at the cost of accuracy.