I've never been to any of mine, and have no intention to start. With limited vacation time and dollars, why give it up to spend a weekend visiting people I have not maintained a relationship with (for whatever reason)...
My parents, both born in the early 30s went to all of theirs. My husband & I graduated in 73 & 75 respectively. He’s never been to a reunion, I went to our 5 year because a friend wanted me to. My BIL graduated with me, he’s been to them all. But he’s a much more social personality than we are. The reunions for my class have been at a local bar. My husband & I aren’t drinkers & have no desire to fake socialize with people we never keep contact with. None of my siblings go to their reunions either.
My kids (now in their 40s) went thru a different town’s school system. That town seems to have 1 reunion for all classes. But again, my kids have never gone to any either.