Also what's your work situation? How much are you able to save each year as a couple? If you're also earning some work income and you're able to max out most of your tax shelters as a couple, the best thing would probably be to put as much of her pay into the 403(b) as they'll allow, and then use the spousal IRA provisions to also fill up her IRA. If you have to pick one or the other, an IRA often (but not always!) has better fees and more choices.