Supplemental health insur: I'm 78 on Medicare. worth the cost of premiums?

I'm now in very good health, though realistic about how a sudden health issue might appear. I discontinued my Suppl Hlth Ins policy due to the recession/limited funds to pay. I now have improved income, but still want to know whether I can get along with Medicare coverage on, say, a heart attack, or other unforeseen problem. If I pay $2000+ a year on premiums but don't really benefit form the coverage, what is the actual dollar picture if, say, I encounter a $30,000 critical need hospital bill? How much would Medicare cover, how much would I need to pay out of pocket?