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Invest in low cost small cap index funds when saving towards retirement?
You can simply stick with some index funds that tracks the S&P 500 and Ex-US world market. That should provide some good diversification. And of course, you should always have a portion of your money in short/mid term bond fund, rebalancing your stock/bond ratio all the way as deemed necessary. If you want to follow the The Über–Tuber portfolio, you'd better make sure that there's minimum overlapping among the underlying shares that they hold.