Advice for the families

Both Kauffman and Cordaro say the Mendells need to boost their retirement savings and fast. That means cutting back on dinners out and reining in some of their purchases. That's especially true since both Dave and Emily want to retire early.

Based on their current savings, the Mendells will have only enough set aside by the time they're 60 to fund nine years of retirement, even with Dave's pension.

Kauffman suggests that they sock away at least 10 percent of their income, up from 5 percent now. And they should shift most of the money out of the cash investments they have in their retirement accounts and into a diversified mix of stock funds.

Even though they're admittedly averse to risk, cash investments won't provide the kind of growth they need in their portfolio to beat inflation over time. As for the kids' 529 college accounts, Cordaro recommends contributing an additional $520 a month.