Life is good, say more than 2,000 senior citizens in a new nationwide survey released in Miami last week.

Almost three-fourths of those surveyed say their past year was as good or better than the previous one. And more than a third of those under 70 expect their quality of life to improve as they grow old.

But other results seen in the first-ever “United States of Aging’’ poll — which asked questions about health, housing, finances and life satisfaction — suggests a peek inside some seniors’ checkbooks and medical files might hint they are poorly prepared for the road ahead.

The National Council on Aging, UnitedHealthcare and USA Today commissioned the telephone survey of adults 60 and older, conducted in five cities or regions: Miami, Dallas, upstate New York, Milwaukee and southern California’s Orange County.

While 8 out of every 10 Miami seniors plan to age in their homes, almost 40 percent of them said they probably would need grandchildren or children to care for them eventually. Twenty-eight percent said they didn’t know if their money would last through retirement or did not have a financial plan, a rate higher than the national average.

And about one-third said they might not be able to pay for an accident or unexpected medical expense, also above the national average.

“I was pleased that there was so much positivity about aging, as a positive attitude has such good impacts on health. But many [elders] have not done necessary planning,’’ said Dr. Rhonda Randall, chief medical officer for UnitedHealthcare Medicare & Retirement.

While 84 percent of those surveyed nationally said they believed they could do what was necessary to maintain their health for the next five to 10 years, only half reported they exercised regularly. “Those engaging in unhealthy lifestyle habits won’t have the ability to age healthy,’’ Randall said.

The poll, which may be repeated annually, aims to gauge if baby boomers are prepared for aging as well as those who retired years ago. The results will be used to create a discussion guide available for communities wanting to run forums on how to better serve their elders.

Seniors with household incomes of less than $30,000 face even greater challenges, as they have fewer resources and tend to be in poorer health, said Richard Birkel, acting senior vice president at the council’s Center for Healthy Aging. Almost half of those with lower incomes polled said they didn’t know if they could meet their monthly expenses in the near future, and 72 percent had at least one chronic health condition.

Max Rothman, president of the Alliance for Aging serving Miami-Dade and Monroe counties, said most seniors looking for assistance are close to 80. About 5,000 are on waiting lists for services like home care.

“I think the biggest problems we keep hearing about fall into the area of financial insecurity and everything that means,’’ he said.