You think you know how to handle your money. But a new Paycheck or Pot of Gold Study from MetLife found that one in five retirees who took a lump sum from a defined benefit (DB) pension or defined contribution (DC) plan depleted it.

On average, it took just 5 1⁄2 years to do so.

The study incorporated an online Harris Poll of more than 700 DB and DC plan participants. Of those who took a lump sum, 63 percent made major purchases within the first year and 22 percent gifted a significant portion of this money to friends, family, or charity.

Roughly one-third of those who made major purchases regretted their decision, and 23 percent who gave money wished they hadn’t.

Taking a lump sum can feel like hitting the Lotto, but the money has to last as long as you do. Here’s how to manage a lump sum at retirement:

  • Think long term

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Restrict how much you take out of the lump sum each year. “Based on how long you’ll take distributions, plan on taking 3, 4, 5 or 6 percent per year,” advises Jason Hill, president, Client Focused Advisors in Manhattan.

  • Create a budget

Figure out how much you’ll need to cover basic living expenses.

  • Be mindful of fees

“When investing, avoid large upfront fees or commissions; this impacts retirement income. Dig deep to determine your investment’s total cost,” says Gregory Kurinec, a registered financial consultant with Bentron Financial Group in Naperville, Illinois.

  • Don’t forget taxes

A lump-sum distribution taken straight from a retirement plan and paid to the retiree usually incurs taxes. Says Timothy Yee, a certified financial planner with Green Retirement in Alameda, California, “Rolling it to an IRA may be better.”