Fidelity's analysis, which assumes the two theoretical people are eligible for Medicare, includes premiums, copays and other cost-sharing expenses, along with prescription-drug costs.
And, it's just a starting point. Things that are not covered by Medicare — dental, basic vision, over-the-counter medicines, long-term care — would be on top of that $285,000 estimate.
The biggest unknown variable for retirees is long-term care, which includes help with daily living activities such as eating and dressing.
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"We recommend that folks think about their family history, look at their relative's health and their own health," Manion said. "It could be a significant cost for some but not for others, and it's hard to predict."
Someone turning 65 has a nearly 70 percent chance of needing long-term care services in the future, according to government data. There are insurance policies that cover those costs, although the premiums can be pricey. Some life insurance also comes with a rider that covers long-term-care costs.
Manion also advises that pre-retirees familiarize themselves with Medicare.
The program, which covers roughly 51 million older Americans, is not free. Part A (hospital coverage) comes with no cost, yet Part B (outpatient coverage) has an average monthly premium of $135.50 for 2019. For prescription coverage under Part D, the average premium is $32.50 this year.