It seems so long ago. But in 2009, many of the wealthy were stunned to find themselves in a cash crunch. Despite all the talk of cash cushions and risk management, many of the wealthy suddenly realized that they had overborrowed, overspent and overconcentrated on a single asset or industry.
We had suddenly entered the new age of the High-Beta Rich, where the wealth was volatile and far more cash was needed to absorb the shocks of financial markets.
Four years later, the lesson still holds.
A study from Spectrem Group asked wealthy and affluent investors "what do you wish you had done differently in the crisis."
(Read more: Retirement, the rich and the superrich)
For the top earners—those making $750,000 or more—the No. 1 answer was "saved more." Ranked second was "done more research about finances on my own" and then "not taken on as much debt."