A recent opinion piece by Barry Katsman in the Jerusalem Post discusses the milestone of one's 50th birthday. He points out how the Zohar explains that the Levites were retired from Temple Service at the age of 50 because their voices no longer sounded so sweet -- and that "the strong fire that is within a man is cooled down". Indeed, the Sforno adds that the retirement age for Levites is the basis on which we know that man's physical decline commences at 50. Grim stuff -- but, as the article notes, reaching 50 has a positive side too: according to Avot 5:25, it is the age at which one is qualified to give advice. Of course, this is only a generalisation, but it is a comforting one for those who have reached the foothills of advanced middle age. And, at 50, whether a person is able to give good advice or not, there is a better chance that he will be listened to.