When using a date fund, it's harder to attain your target asset allocation if you have any other retirement savings. I'm currently in VEMAX (emerging markets) and VTSAX (total stock market), along with Wilshire 5000 and EAFE (Europe-Australia-Far-East) from another account. I do the balancing myself with a simple one-page spreadsheet. (25% bonds, 75% stocks (35% international, 65% domestic)). All of my bonds are medium term US government securities. Date funds do the rebalancing for you, but they don't take into account your other holdings, nor your personal risk tolerance.