John Scalzi said this quote

Then you're seventy-five, friends are dead, and you've replaced at least one major organ: you have to pee four times a night, and you can't go up a flight a stairs without being little winded -- and your're told you're in pretty good shape for your age. [....], in a decade you'll be eighty-five, and the only difference between you and a raisin will be that while you're both wrinkled and without a prostate, the raisin never had a prostate to begin with.