Which of the following is not a feature of a 529 college savings plan?

A 529 college savings plan is designed to encourage saving for future education costs, and it's important to understand its features. One of the key characteristics of these plans is the flexibility regarding when the funds must be used. There is no requirement that the account holder must use the money by the age of 30. In fact, funds in a 529 plan can generally be used for qualified education expenses at any eligible educational institution, and there is no age limit for when the funds must be spent. This flexibility allows for planning around various educational needs beyond just traditional college or university expenses.

The other features mentioned highlight the benefits of 529 plans: tax-free growth on investments when used for qualified expenses, the option to use funds for K-12 education including private prep schools, and tax-deferred growth of the money until it is withdrawn for use. All these characteristics support the overall intent of the 529 plan to facilitate education funding without unnecessary constraints.