Great story with worthwhile information. To simplify further, an investor could put 50% of their savings in a total stock market fund and 50% in a total bond market fund. Fundamentally When stocks fall bonds usually rise. In most cases the custodial and tax fees are minuscule and your investment will do as well as any, unless you are trying to time a sector or the market, which is gambling. You can rebalance at any time. As you pointed out, over time, your investment will grow very well and quickly. You can look at the scenarios online at Vanguard or Fidelity or another reputable brokerage firm.