Poor seniors die up to 9 years sooner than the wealthiest ones. How not to be one of them.

Billy Joel famously sings that only the good die young, but a recent study shows it’s really the poor who are dying young.

Older people who earn less than $20,000 a year die nine years sooner on average than those who earn $120,000 or more, according to a study by the National Council on Aging (NCOA) and University of Massachusetts Boston's LeadingAge LTSS Center. Middle-income seniors who earn around $60,000 die three years earlier, it said.

With income inequality growing and more seniors falling into poverty each year, this is an ominous sign for the largest surge of Americans turning 65 daily in history, experts said. But with proper planning, it doesn’t have to be, financial advisers said.

“There’s no 'too young' of an age to plan,” said Brian Davis, San Diego-based financial adviser with Northwestern Mutual. “I have clients in their 20s talking about long-term planning.”

On the other end, “it’s also never too late,” he said.