Social Security is a valuable source of income for tens of millions of retired workers, disabled workers, spouses of workers, and more. And with pensions declining in popularity in recent years, Social Security is the only source of inflation-protected income many retirees have,

Donald Trump had no shortage of promises throughout his campaign. He vowed to end the federal income tax on Social Security benefits, for example, as well as eliminate tax on overtime pay and tips.

The process behind calculating the COLA remains a mystery to many. Here's what every retiree should know about how the COLA is determined and what changes might be on the horizon.