Kaiser Family Foundation does a good job of explaining how the republican plan would change Medicare. It has a chart that shows how much a person would pay out of their own pocket for Medicare.
Ideally, people would be saving throughout their lives to cover these expenses, but many people barely cover regular expenses during their working life. It's a reality that republicans don't ever reckon with. The very least we can do for people in this country is to make sure they get health care when they're old. Sure Medicare needs to be fixed so it doesn't run out of money, but the republicans have much too much zest for overhauling Medicare.
I don't understand how the people who voted republicans to power in the midterm elections didn't understand that republicans were serious about cutting spending.
Entitlement programs, such as Medicare and Social Security, make up a large part of spending. It was amusing to watch people in funny hats rail against the democrats while saying "don't touch my Medicare" but we all pay for stupidity. In a way, I'd like to see republicans do their thing, that way people would learn that they shouldn't vote blindly.