I wanted to spare my kids the burden of student debt — but I made 1 huge mistake with their 529 plan. What I’d do differently if I could go back (and what you can learn from my missteps)

Two decades later, the 529 still bulges — largely from investment gains. Cashing out for non‑education expenses would trigger ordinary income tax plus a 10 % penalty on the earnings portion, according to the IRS.

Now, you’re asking the same question many savers face: How much is too much to save for your kids' college, and what are your options if you overshoot?

Here's what you need to know about 529 plans and what to do with what’s left over.

What are 529 plans and how do they work?

A 529 plan is a tax‑advantaged investment account specifically for education costs. Anyone can open one and name a beneficiary (like a child, grandchild or even yourself). There are typically two types of 529 accounts:

• Savings and investment plan: You save money in a 529 investment account. Growth is tax-free if used for qualifying expenses. This is the most flexible plan, as it can be used for K-12, college and apprenticeships.
• Prepaid tuition plan: This plan locks in today's tuition rates, usually for in-state, public colleges, and is less flexible.

There are several benefits of a 529 plan, including tax breaks and the ability to control investment options. You can also switch the beneficiaries of a 529 investment plan, too. For example, you can change it from yourself to your child, and then your niece or nephew, depending on how you plan to use the funds.

However, there are also a few drawbacks. If you pull the money for non-educational expenses, you'll pay income tax plus a 10% penalty on the earnings. There is also some market risk. If the market crashes when your kids head to college, you could end up with less cash than expected.

And there's a chance you won't need all the funds. So, what happens if there is money left over? There are a few ways to use it.

First, you can save money and pull it out during your own retirement. Your income will be lower, so you'll pay less income taxes. You will still pay the 10% penalty, but remember, that is only on growth. Other options include:

• A Roth IRA rollover: Under SECURE 2.0, up to $35,000 of a 529 (held at least 15 years) can migrate to the beneficiary’s Roth IRA, subject to annual IRA limits and income requirements.

• Other qualified training: Graduate school, trade programs, student‑loan repayment (up to $10,000 per lifetime) or even qualified international study count, too.

• Changing the beneficiary: Swap the account to cover college costs for another child in your family — a niece, nephew or even a grandchild down the line. Or, switch it to yourself and get that pottery certificate in Tuscany you've always dreamed of. (Just make sure it's eligible first.)

How to make the most of 529 plans — and avoid common mistakes

Consider using these strategies to hit the sweet spot — big enough to cover most costs, but small enough to sidestep penalties and wasted growth.

Set a realistic target

Estimate the cost of four years at your state university, then add a small cushion (maybe 20 %). Adjust annually as tuition data updates. If your child ends up choosing a pricier school, you can cash‑flow the gap, apply for aid or take out student loans. This will prevent over-saving and give you more flexibility to save more for retirement or finance other goals.

Coordinate with relatives early

Ask grandparents and other family members if they plan to pay directly or fund their own 529 plan. It can be tough to have these conversations, and people may not know yet how much — or if — they can contribute. However, starting the discussion early can help you balance savings.

Time your contributions

Front‑loading (saving more when your children are very young) can turbocharge growth and reduce the risk of overfunding if plans change. Revisit the goal each year and decide how much is right to contribute. By high school, for example, you might realize your child is likely to attend a trade school, so you may readjust your contributions.

Limit risk as you get closer to graduation

Consider reshuffling the portfolio during each year of high school to mitigate risk. That locks in gains and shields you from a late‑cycle crash. Much like moving to reduce risk as you get closer to retirement, this helps protect your funds before you need them.

Know your escape plan

Even with careful planning, you could end up oversaving. Make sure you have a plan now for where the funds will go. Leftover funds can be rolled to another relative, converted to an IRA for your kids, pay for your own training or used to bolster your retirement savings.

Aim for moderation when funding a 529; save enough to cover a solid in‑state education, keep other savings on track and stay flexible. That way, you won’t end up with a tax headache when those Ivy League dreams turn into a state school reality.