Using a 529 account for additional savings is a suggestion I hear from time to time, mostly from super-savers who have already maxed out their retirement accounts and want to save more for their retirement.
Occasionally I get some version of it from those who have saved a great deal in 529s and wonder if perhaps they have over saved for college and can just use the leftovers for retirement.
The maximum protection occurs when the child owns the account, of course, since it is no longer your asset, but you obviously lose control when you do that
The main 529 account rule is that if you spend the money on something other than education, you will have to pay regular income tax plus a 10% penalty, but only on the earnings, not the basis.
Disadvantages of a 529 Plan for Retirement Savings
They’re far better than a taxable account, retirement accounts, and the myriad of insurance schemes proposed for this purpose. But 529s are not a “Stealth IRA” by any means. Plan on spending yours on someone’s education.