How old was LO before they went to Grandma's or Grandpa's (or any other relative) for an overnight visit without you?

My brother and I were 10 and 12 before we ever spent a night at our grandparents' house without my parents (my grandparents lived 2 hours away at the time). It was summer break and my parents had to work so we spent four days with my grandparents.

I could see sending LO to my parents' house for one overnight or a weekend, once they're potty-trained (they're about 2 hours away) but I just don't really see a need for just one overnight or a weekend, so they'll probably be much older, like 10, before I'll take them up there and let them spend a week in the summer.

DH's family lives much much further away and I don't see any reason to ever send them solo (it would involve a flight with multiple stops and changing flights) and I just wouldn't feel comfortable with that until they were 15-16 but at that age, I doubt they'd want to go spend a week away from their friends and stuff.

When did you send your kid(s) off to Grandma's (or whoever)?