I guess I have to ask the question: what’s the purpose behind the question?
Are you trying to size an appliance or is there some other reason?
A sizing tool for this purpose is planned.
CPLogInvestigator will tell you how many logs a given server has.
Non-firewall logs generally are already summarized (to an extent) and could be considered events on their own.
Firewall logs take the most work to “summarize” to events and the volume of logs that turn into events can vary.
I’ll have to see if I can find the estimations I used for this exercise previously.