According to William Bengen’s study, published in the 1994 Journal of Financial Planning, the amount a retiree can withdraw each year from their portfolio is somewhat related to market volatility and the sequence of their investment returns.  Therefore as retirees manage investment risks, the size of their withdrawals, and market volatility it’s possible to improve their retirement outcome.  Additionally, according to a Vanguard study, investment advisors can improve an investor’s situation using well-known and accepted best practices for wealth management compared to those of portfolios that are not.