Medicare helps to pay for the healthcare expenses of more than 50 million Americans, making it one of the country's most popular and important social programs. Learning all the ins and outs of the system can be a bit complicated, but if you rely on the program for your carem then it's worth putting in some effort to make sure you know what's covered.

With that in mind, we asked a team of Fools to highlight a little-known Medicare benefit. Read on to see what they had to say.

Tackling depression

Todd Campbell: Once a year, every Medicare Part B recipient can receive free depression screening from his or her primary-care doctor.

That's important, because one in six seniors suffers from depression, and many of those seniors are either undiagnosed or under-treated for their disease. According to WebMD, only 10% of chronically depressed seniors receive the treatment they need for their disease.

Depression is a particularly serious matter for seniors, because studies show that it can lead to other health problems, such as cardiac diseases, and it can increase the risk of death. Depression has been linked to poorer outcomes among nursing-home patients, and sadly, seniors' suicide rate is higher than it is for any other age group. Clearly, Medicare's depression screening is critically important to maintaining health in your golden years.