The document provides an overview of Medicare, which includes four parts (A, B, C, and D) that cover different health expenses. However, Medicare does not cover all health care costs in retirement. It outlines what each part covers, average premium and out-of-pocket costs, and expenses that are not covered. It recommends retirees understand what costs they will be responsible for, evaluate insurance options to cover gaps, and develop a retirement strategy that accounts for health care expenses.