Many retirees are surprised to learn that Medicare isn't always a fixed cost. If your income exceeds certain thresholds, Medicare can charge significantly higher premiums through a little-known rule called IRMAA (Income-Related Monthly Adjustment Amount). Even more surprising, those higher costs are often based on income from two years ago rather than what you're earning today. In this episode, Jeremy Keil (Mr. Retirement) explains how IRMAA works, why Medicare uses prior-year tax returns to calculate premiums, and what retirees need to know when planning Roth conversions, managing retirement income, and preparing for required minimum distributions. He also shares real-world examples of retirees who successfully appealed their Medicare surcharges after retirement reduced their income. If you've received an IRMAA notice—or want to avoid being surprised by one in the future—this episode will help you understand your options and how Medicare costs fit into a broader retirement tax strategy. For disclosures and conflicts visit keilfp.com/disclosures.