Among 55-plus working households, four in 10 have saved at least a quarter-million dollars for retirement, according to a long-running retirement confidence survey.

Is that enough to maintain their lifestyle in retirement? It's difficult to say without knowing the full range of assets and matching them to former income.

However, this top group in the Employee Benefit Research Institute survey does have enough to attract the attention of unscrupulous advisers and salespeople.

Attorney Andrew Stoltmann, who represents lottery winners, finds a lot of similarities between the lucky few and the masses of near and new retirees getting ready to roll over their 401(k) savings on their own.

Part of the problem is overconfidence. EBRI and Greenwald & Associates found a troubling disconnect between workers' overall level of savings and their confidence in a secure retirement.

The Retirement Confidence Survey found 67% of workers feel confident that they have enough resources to retire comfortably, yet a relative few have spent much time creating formal financial plans and many have not saved enough. "Early mistakes can doom a lottery winner or a retiree in much the same way," he said.

Here are the most common mistakes that Stoltmann sees:

Missing the risk target. Misjudging how conservative or aggressive to make the portfolio can make a pot of savings either needlessly volatile or so conservative that it gets eaten by inflation.

Lottery winners and retirees often are thrust into a risk profile very different from what they've had in the past, so they are particularly vulnerable to errors. The trick is to ask questions about how any investment manager arrived at the risk profile being recommended.

Paying too much. Drill down on the cost of investing (expense ratios of mutual funds and ETFs, for example) and then ask how the firm charges for advice. Compare the total fees your prospective adviser will charge with what your old employer charges. Most 401(k) plans allow retirees to leave assets in the plans, though few have easy-to-use mechanisms for drawing regular income.

Failing fiduciary. Fee-only financial advisers tout their pledge to put the interests of customers ahead of their own. But that doesn't mean they are free from future temptations toward fraud. And digging deeper, are they truly providing usable tax advice? Using a robust withdrawal strategy? In short, earning their fee?

Janet Kidd Stewart writes for Tribune Content Agency.