I think it varies for everyone. We just attended DH's 50th Grade School reunion. Had about 35 people there. Nice thing is that many of the grade-schoolers attended the same high school. His class has stayed close, and we've attended all of the reunions. My 45th is this fall, and we'll attend that also. I've remained close with many of my classmates, and the reunions have become warm, laughter filled fun times. I met DH one year after graduating, so have known some of his friends "forever"!! In fact at his last reunion they had me listed as a class member!