Just a word about the idea that the school will pay if she does a PhD, since you seem to appreciate long term planning. What this actually means is that they will pay her subsistence wages to TA or RA. This is all fine, and fair, and good. However, what a lot of people don’t think about are the opportunity costs of that. If she gets a PhD, she will lose about 6-7 years of earnings and contributing to a 401k in her 20s, so she will be way behind in the financial game of life when her 50s and 60s roll around. It would be very nice for her to have some money from that 529 to supplement her PhD years, if you can swing it. Also, most PhD candidates I know are not able to actually live on the amount they are paid and end up taking some loans as well.