More than 1.5 million baby boomers are now signing up for Medicare coverage, but there is now considerable uncertainty about the future of the program.

No matter who is elected president later this year, there will likely be significant changes to the country's Medicare program. Plans released by both the Obama administration and top Republicans include limiting spending growth for the program, taking more money from those in higher income brackets to fund it, and perhaps even raising the eligibility age.

The biggest rift between the two plans is whether to privatize Medicare, either in whole or in part. Currently, about 25 percent of recipients participate in the privatized program known as Medicare Advantage.

This change comes as researchers had recently estimated that between 20 percent and 30 percent of the $500 billion or more that Medicare spends every year is used on treatments and procedures that provide patients with little or even no benefit.

Many people in retirement face significant medical bills that can make it difficult to afford treatment, especially given that Americans' life spans are growing longer all the time.