'Eighty' in the Bible

But Barzillai was very old -- eighty years old, in fact -- and he had taken care of the king when he stayed in Mahanaim, for he was a very rich man.

I am presently eighty years old. Am I able to discern good and bad? Can I taste what I eat and drink? Am I still able to hear the voices of male and female singers? Why should I continue to be a burden to my lord the king?