When you have already created a million dollar net worth, you have come a long way to create a multi million dollar retirement. You have already demonstrated that you have the skills to create wealth. Now is the time to learn the skills to multiply wealth. In many cases, this skill set to multiply wealth needs three main steps. 

Firstly, it needs you to make your work harder for you, than you working harder for money. This means, your money needs to be invested at the right places and at the right time. Knowing that there is no perfect strategy to time the market, it all comes down to thinking long term and putting your money in a diversified asset basket. 

Secondly, it requires you to become less emotional about money over time. As we generate wealth and have kept enough funds aside as emergency funds for the near future, we can become less emotional about money matters and make more rational decisions around money. It requires us to bet more on mathematics...