Community Answers (5)
At 10, I brought this up with my son and he said it sounded "scary" so I dropped it.
At 11, I brought this up and he said it sounded okay, so I left him during the day and walked to the neighbor's house for a half hour trial run. He knew where I was, how to get there, how to call me and when I'd be back. After that, I would leave him to run to the store (30 minutes trip) only during the day.
By 12, he was good with longer time periods and sometimes after dark. By this time, we had a year of discussions on when to call mom, when to call the fire dept, when to call the police, when to call an ambulance, when to call the neighbors. He could handle anything in the normal course of events and we had discussed how to handle emergencies. He knew the rules of staying on his own (no cooking except microwaving, nobody allowed in the house, no leaving the house, even to play in the yard, except in cases of emergency, keep his phone near him and turned on).
My long-winded reply is really that it isn't a specific age. It's dependent on the child when you start the process and important that you consider it a process, not an immediate step.