When do you think is the right time for kids to stop playing with toys?

It is really up to the parents and how responsible the kids are, but not buying the one year old toys is bull. I am kind of a "big kid" myself because I am 25 and will still play barbies with my 5 year old niece. She can play SOME xbox games, but is supervised so she doesn't lose them or scratch them. But as it is your BOYFRIENDS SISTER, there isn't anything you can do about it because they are not your kids. I had to learn that the hard way...