Every few years, a new investment trend captures headlines, from crypto to gold to private equity and real estate. But for retirees, the real question is not what is popular, it is what supports a sustainable income plan for the next 20 to 30 years. Before adding alternative investments to your portfolio, here is what you should consider.

Bitcoin has been one of the best-performing assets of the past decade. Keep in mind that the last decade has also included record-smashing highs for both the DJIA and the S&P 500. When something is successful, people copy it.