Traditionally, some financial advisors or some asset allocation calculator tool to automatically adjust what it invests in (usually a mix of stocks, bonds and cash) to maximize your return and minimize your risk. For example, as you approach retirement age, most experts agree you should change asset allocation investment strategy, and gradually shift more into bonds to protect the money you've accumulated. But retirement can last a few decades, so it generally pays to maintain a healthy dose of stocks well into retirement: possibly between 40% and 50% while you're in your 70s, and up to 30% when you're in your 80s.

The old rule of thumb used to be that you should subtract your age from 100 - and that's the percentage of your portfolio that you should keep in stocks. For example, if you're 30, you should keep 70% of your portfolio in stocks. If you're 70, you should keep 30% of your portfolio in stocks. However, with people living longer and longer, many financial planners are now recommending that the rule should be closer to 110 or 120 minus your age. That's because if you need to make your money last longer, you'll need the extra growth that stocks can provide.

In an interview CNBC with ARK Invest CEO Cathie Woods on Monday, March 8, she said she believes cryptocurrencies could stabilize and eventually behave like bonds. A 60-40 portfolio that’s split between stocks and bonds may look more like 60-20-20, Wood said. That is, 60% in equities, 20% in bonds and 20% in cryptocurrency. Bitcoin and other cryptocurrencies could eventually become part of the recommended portfolio for everyday investors. “We think as it becomes a better accepted new asset class ... We do think it will behave, actually, I would say more like the fixed income markets, believe it or not,” Wood said.