I'd love to see this plugged in to a tool that asks 1) What allocation percentage of stocks/bonds do you want, 2) What length of period in years (i.e. 20 years,

I'd love to see this plugged in to a tool that asks 1) What allocation percentage of stocks/bonds do you want, 2) What length of period in years (i.e. 20 years, 40 years), 3) What confidence level (50%, 75%, 90%) and yields what APY you can expect. (The higher the confidence, the lower the APY.) I'm still convinced that the general advice out there is highly out of whack, and that someone's expected returns should be very low. I'm currently modeling under 2% (post-inflation, more like 4% with) for the future, for a simple allocation model and a 10-year window.