The market cycle theory is a great tool for any investor these days. I has also described this subject in my article here: https://medium.com/@richierichard/what-should-you-do-with-bitcoin-now-274c50ed4791 where you can find more advice on risk management techniques.

On the other side, this theory is not universally applicable. For example, market cycles don’t work for assets which do not have any fundamental value. For example, tulips in times of Tulip mania.