Close friends contribute to our personal growth. They also contribute to our personal pleasure, making the music sound sweeter, the wine taste richer, the laughter ring louder because they are there.
Had I to give advice to writers (and I do not think they need it, because everyone has to find out things for himself), I would tell them simply this; I would ask them to tamper as little as they can with their own work. I do not think tinkering does any good. The moment comes when one has found out what one can do - when one has found one's natural voice, one's rhythm. Then I do not think that slight emendations should prove useful.