I have a 9 yr old stepson who happens to be very resposible and mature for his age. still I would never leave him at home alone this young for any period of time. He does however get 'practice' so to speak for when this will eventually occur. we live in the country on 7 acres and my father lives around the corner on 12 acres. he and his 7 yr old brother constantly play unsupervised all over the place and in the timber. I think they're old enough and quite capable to be unsupervised for some period of time with their father and I as well as "grandpa john" close at hand. We did however get them these walkie talkies that have a twenty mile radius and are chargable so we don't have to worry about dead batteries ( they work great). They take one with them when they play out of our sight range and we keep the other so we can check in on them every so often and let them know when to come home or so they can notify us, god forbid should they get hurt. we just recently moved out there from the city and we used them there too when they would play at a neighbors house outside. however they never wondered further than the neighbors unsupervised in the city. It's not that you can't trust your children to be alone and to know, respect, and abide by the boundaries you've set for them to follow in your absence, its that you can't trust other people.