Excerpt: [W]hile it may be useful to see how your 401(k) compares in riskiness to the S&P 500 or where it ranks on the scale from conservative to speculative, I don't think this is the most important thing .... Far more essential is finding out whether you're on track to achieving a secure retirement. Which means you want to know whether the portfolio you accumulate by the time you retire, plus Social Security and any pensions you may receive, will be sufficient to support you[.]