However, many financial planners and analysts have gone back and revised that belief. The rule of thumb to base calculations off of 100 has been revised to a higher 110 to 120 range because there just wasn’t enough growth in portfolios that used the lower figure. Based off of 120, a 50-year-old should have 70% invested in stocks rather than 50% – a more aggressive approach, but one that seems to be more widely accepted as the better way to invest, even for conservative investors.

Research conducted by Michael E. Kitces and Wade D. Pfau showed that asset allocation works well without any adjustments at all with a 60/40 split weighing more heavily in stocks. This simple setup showed steady long-term growth that rivaled some of the most complex multi-stage strategies and outperformed portfolios that followed a sliding weight scale that changed its allocation percentage over time to become more conservative.