Someone sent me an email the other day where they quoted a section of a legal document. Each sentence started as a new paragraph and each paragraph was preceded by "firstly", "secondly" and so on. And so on! It went on to "seventhly". There may have been more but this is where the quoted section stopped.
I've only ever heard people go as far as "fourthly". Is "seventhly" really correct? Where does one stop? Can I say, "twenty-firstly" the next time I argue with a customer service rep? Or "ninety-secondly" when I'm refuting someone's lowball valuation of one of my portfolio companies?