The stock market is currently very highly priced so many feel now is far from an optimal time in which to jump in with both feet.
This is evidenced by the Shiller PE ratio which is at 37.27 today - Cringe!!!:
Shiller PE Ratio - Multpl
Buffett has been selling huge amounts of AAPL and BAC to lock in capital gains. He has been a net seller of stocks and has built up an enormous cash reserve. This may in part be motivated by looming future tax increases on C corporations. Inflation has been horrible over the last 3+ years as anyone who shops for groceries, purchases gasoline and such will verify. We have been experiencing the worst inflationary period since the late 1970s -No one can predict if, when and how it will end.
United States Inflation Rate
I wish I could offer a solution but I have none. All I can say is I have built up my cash reserves to the highest percentage of investable assets they have ever been. I am mostly in T bills but also some AMT free munis.