FYI, every company charges a 401k/403b administration fee on top of their expense ratios for individual funds. For some reason, this fee doesn't get much press. Vanguard charges $15 per fund (that is PER FUND, not per account). So, if you have $10,000 divided into 3 Vanguard funds with an average expense ratio of 0.15%, you'll be paying $15 annually in fund expenses (the expense ratio) and $45 annually for the plan administration fees. So, your diversification into three funds instead of one fund just doubled your annual expenses from $30 to $60. I would contend that at least while your 403b is rather small, it is best to just throw everything into one fund to minimize your fees, even if that one fund has a somewhat higher expense ratio than the individual funds you are considering. If you want US/International/Bond exposure, just get the target date fund that matches your desired allocation and reevaluate in a couple years when you have a larger account balance.
