Yep most friendships are fluid, I don’t expect anything to last either. I agree fair weather friends are easy to find, I think most people are fair weather friends and have fair weather friends. In terms of people having friendships since childhood, I actually think most of them had a small hiatus in the friendship where they weren’t talking and it doesn’t even have to be for a bad reason. Just the passage of time can separate people and bring them back together, I never had a life long friendship either.