The program gave birth to the idea of retirement and covers nearly all Americans — but now it faces major financial and customer service challenges.

Similarly, Social Security recipients are eligible for cost-of-living adjustments, or COLAs, so that their benefits are able to keep pace with inflation. Many Social Security recipients end up collecting a monthly benefit for several decades. If those benefits weren't eligible for COLAs, they'd be almost guaranteed to fall behind on bills.

When President Franklin Roosevelt launched Social Security at the height of the Great Depression, he wanted to reduce rampant poverty among seniors. Along with Medicare, which debuted 30 years later,