Сочинение на английском "Почему школьная дружба не может длиться вечно?"

During many centuries people all over the world can't imagine their lives without friendship. Friend - is a person, who helps and supports you in any situation/ It is a well-known fact, that practically every person on the Earth found his friends at school/ So why school friendship can be constant?
I personally feel that school ages are the perfect time to make friends. Only then you can live without problems and responsibilities. You can communicate with contemporaries  and get pleasure from it. By the way, children can detect lie and meanness better than adults. That is why, friendship in such a young age is the most sincere.
 But when you grow up, you find new interests, new priorities and old friends lose value in your eyes. Moreover,you and your friends can choose different life's roads and this fact destruct your relationships at all. 
But instead of all facts, you shouldn't forget about the idiom "A friend is never known till needed." No matter how and where you met your friend: at school or university, pab or cafe, you will always detect :your" person, who will be your anchor during the whole life.