Looking out 15 years, the expected 15 - year total return approaches 4.4 % annually, and at that horizon, investors are unlikely to lose money even if actual returns are a standard deviation below our expectations. (hussmanfunds.com)
This Vanguard paper on retiree spending from a potfolio (total return approach vs. total income approach — A really good read for investors nearing or in retirement!) (yourPFpro.com)