Great question. It really depends on how mature and responsible your child is. Generally from the age of seven has worked. They understand the nature of sleepovers from that point. Once you get to know the parent of the child inviting your child to a sleepover is also necessary.
I would say about 9 years old.
It is a good age, not too young and not to old.A time when they can really enjoy it...and still be a little sensible, so it will not cause the host and concerns.
Any younger and I think the child would be way too excited, and that means problems...if a few kids together.
It depends on how much trust you have in the family. I believe that some parents are now doing a police check on prospective hosts. Unfortunately it is not simply a case of age, or even whether the hosts are actually members of the family. I think I've read too many horror stories in the media.
My son had sleepovers with his grandparents from a very early age, however, when it comes to friend sleepovers, I think 9 or 10 is a good age to start. It gives the parents a nice break and teaches the child a little bit of independence.
I think it depends on how well you knwk the family. I would be fine with a sleepover for a 5 or 6 year kid with close family friends, but it would be older than that, maybe 7 or 8, with school friends, and of course I would want to get to know the family first.
I think it depends more on how much you trust the parents your sending your child over to. If you believe they can look after your child well, then I would say 5 was a perfectly acceptable age. As long as you think the child can cope being away from their parents for a night, then it is fine. Also consider how well behaved your child is. You don't want to be putting any unfair angst on another parent.
I was never allowed to have a sleepover when i was a kid. I also didn't let my child have sleepovers wither. I think they are a silly thing actually but when my child was young, i was always embarrassed and full of angst if they were invited to a sleepover…….I just didn't trust anyone to care for my child and I couldn't get my head around why people invited kids without consulting their parents first (to avoid the tantrums and complaining). I never expected parents to trust my husband and i and i didn't ever pressure any other parent to leave their child in my care (for sleepovers).
I think you don't just have to know the parents very well, there an be teenage brothers in the house and, well, yeah just couldn't allow it.