"Current conditions reinforce what has been growing apparent for the past several decades: Rather than chasing ever-shrinking income sources -- and risk under-diversifying and courting extra volatility in the process -- retirees should focus on generating cash flow in retirement instead.... This grouping includes Social Security ... income from working ... income from passive non-portfolio sources such as property rentals or royalties ... [and] cash values on life insurance as well as reverse mortgages."