And while some vaccines do need boosters, chickenpox doesn't need one. The vaccination normally gives lifelong immunity. That's why they don't normally give boosters for it.
Ping
We debated the chickenpox vaccine for our kids, because getting the disease is just annoying, not usually threatening, and then you are safe, but there was no evidence yet that the vaccine would last a lifetime, and so by vaccinating we were taking a risk that they could get the disease at adulthood.
I think we ended up vaccinating anyway. Although I think one of them actually got a mild case FROM the vaccination or something.
I had it when I was a kid.