Dear Liz: My husband and I have been putting 5% and 6%, respectively, into our 401(k) accounts to get our full company matches. We’re also maxing out our Roth IRAs.

The CPA who does our taxes recommended that we put more money into our 401(k)s even if that would mean putting less into our Roth IRAs. We’re also expecting our first child, and our CPA said he doesn’t like 529 plans.

What’s your opinion on us increasing our 401(k)s by the amount we’d intended to put into a 529, while still maxing out our Roths, and then using our Roth contributions (not earnings) to pay for our child’s college (assuming he goes on to higher education)?

Our CPA liked that idea, but I can’t find anything online that says anyone else is doing things this way. I can’t help but wonder if there’s a catch.

Answer: Other people are indeed doing this, and there’s a big catch: You’d be using money for college that may do you a lot more good in retirement.

Contributions to Roth IRAs are, as you know, not tax deductible, but you can withdraw your contributions at any time without paying taxes or penalties. In retirement, your gains can be withdrawn tax free. Having money in tax-free as well as taxable and tax-deferred accounts gives you greater ability to control your tax bill in retirement.

Also, unlike other retirement accounts, you’re not required to start distributions after age 70 1/2. If you don’t need the money, you can continue to let it grow tax free and leave the whole thing to your heirs, if you want.

That’s a lot of flexibility to give up, and sucking out your contributions early will stunt how much more the accounts can grow.

You’d also miss out on the chance to let future returns help increase your college fund.

Let’s say you contribute $11,000 a year to your Roths ($5,500 each, the current limit). If you withdraw all your contributions after 18 years, you’d have $198,000 (any investment gains would stay in the account to avoid early-withdrawal fees).

Impressive, yes, but if you’d invested that money instead in a 529 and got 6% average annual returns, you could have $339,000. At 8%, the total is $411,000. That may be far more than you need — or it may not be, if you have more than one child or want to help with graduate school. With elite colleges costing $60,000 a year now and likely much more in the future, you may want all the growth you can get.

You didn’t say why your CPA doesn’t like 529s, but they’re a pretty good way for most families to save for college. Withdrawals are tax free when used for higher education and there is a huge array of plans to choose from, since every state except Wyoming offers at least one of these programs and most have multiple investment options.

Clearly, this is complicated, and you probably should run it past a certified financial planner or a CPA who has the personal financial specialist designation. Your CPA may be a great guy, but unless he’s had training in financial planning, he may not be a great choice for comprehensive financial advice.