$ave Me: Act now to save on health care next year

For a healthy, wealthy 2014, now is the time to take action.

Many companies have started or soon will start their open-enrollment period, when employees select a health plan and make choices about other benefits.

These are important decisions, considering that medical costs are expected to rise 6.5 percent next year, according to PwC Health Research Institute. Though that's less than the 7.5 percent jump they expected this year, it could still add hundreds to out-of-pocket costs.

Open enrollment isn't just about picking the right health plan. It's also your one chance to set aside pretax cash for next year's health-care, commuting and child care expenses—something most employees don't do. Only 24 percent of workers with access to a flexible spending account fund one, said Joseph L. Jackson, CEO of WageWorks, a benefits administrator.

That's an expensive miss. Someone in the 25 percent tax bracket could see federal tax savings of roughly $1,250 by setting aside $5,000 a year for child care.

—By CNBC's Kelli B. Grant. Follow her on Twitter @kelligrant.