Many retirees are finding that their golden years aren’t so golden after all. The face of retirement is changing, driven by the disappearance of pensions, a fragile Social Security system, inadequate savings – and lives that last longer than ever.

That final factor may be the most significant of all. Medical advances keep lengthening our lives. Someone who reaches age 65 can expect, on average, to live another 19 years, according to the Centers for Disease Control. Some people, of course, will live even longer than that.

That’s great news in general, but it can play havoc with retirement planning, as many baby boomers are finding out.

“When you live longer, you’re money needs to last longer,” says Mark Fried, president of TFG Wealth Management (www.tfgwealth.com) and author of Road Rules for Retirement.

“But a big problem is many people still hold fast to a retirement model based on a much shorter lifespan. They don’t consider that their retirement could last three decades or more, and so they don’t plan how to pay for that.”

Fried says a few things people should take into account as they prepare for what could be a decades-long retirement include:

• The effects of inflation. The rising cost of living can be an insidious enemy for retirees. For example, a 3 percent inflation rate over 24 years could cut purchasing power in half, Fried says. “That means if you retired at 60, by the time you reached 84 you would need twice the dollars to maintain the same standard of living,” he says. “Over time, inflation can destroy wealth. As they plan for retirement, it’s critical that people factor in the effect inflation could have on their savings.”

• Social Security’s present and future. “Our longevity is at the root of the problem with Social Security,” Fried says. When Social Security began in the 1930s, most people didn’t live long after their working days ended. There were also plenty of young workers who could be taxed to pay for the retirees receiving benefits. Both those factors have changed. One result is the government has limited the year-to-year increase in benefits, Fried says, which means Social Security won’t replace as much of your pre-retirement income as it once did. Some people may want to delay collecting benefits until they are 70, which increases the monthly amount. Regardless, he says, everyone will want to make Social Security decisions based on how that affects other parts of your retirement-income plan.

• Personal savings. There was a time when many Americans had generous pensions that lasted as long as their lives did. Fewer and fewer retirees can count on such pensions today. Instead, many employers shifted to a 401(k) plan. That meant employees became investors who needed to accumulate enough money to last a lifetime – and many weren’t good at it, Fried says. “Some failed to diversify, keeping much of their money in company stock,” he says. Despite that, he says employees should participate in a 401(k) if they have the opportunity, especially if the employer makes a matching contribution. “But that might not be enough,” Fried says. A good rule of thumb is that 15 to 20 percent of your gross salary should be stashed away for retirement.

“Longevity impacts a wide range of retirement decisions,” Fried says. “That key thing to remember is that you can’t expect the strategies of two or three decades ago to work today. It’s a new game.”