Of course, your own ideas of where investments will be going should enter the conversation.
Retirement Planning Ain’t What It Used to Be | ThinkAdvisor
https://www.crestmontresearch.com/docs/Stock-Waiting-For-Avg.pdf
The problem is NOBODY knows where the market will go, short, medium, or long term. There has been way more folks wrong over time than right. Be invested, diversify, rebalance, and plan with other money according to your needs, wants, desires, and time horizon. The guys in these articles can just as easily be wrong or they might be right, or somewhere in between.