Leaving work four years before starting Medicare can drain $100,000 or more from retirement savings. It pays to consider all the possibilities. Retiring before 65, whether by design or dictated by circumstance, is a reality for many Americans. And health insurance for these early retirees is often more costly than they think—and a reality check. For a couple, premiums for coverage can run from $1,700 to $2,200 a month depending on where they live, their age and the source of the insurance.