20 timeless money rules

Performance comes and goes, but costs roll on forever.
--Jack Bogle

If you choose a fund that eats up 1.5% a year in expenses over one that costs 1% (let alone the 0.2% that index funds may charge), your fund's return will have to beat the other's by half a point a year just for you to come out even. Past returns are no guarantee of the future, but today's low-cost funds are likely to stay low cost. Buying them is the only sure way of giving yourself a leg up.