Kids beyond fifth grade are expected to be able to navigate to and from school independently. And the standard for other situations is based on can you reasonably expect they can take care of themselves and the other kids under their supervision. There is a lot of case law about it, so it isn't ok to leave your kid home alone and go out to a bar or a party, but it is ok to either go to the deli or send them. Again this is restricted to if you can reasonably feel they can be safe in what ever scenario you leave them in. I live in Midtown Manhattan and my Wife really pushed ahead compared to everyone else getting our son independent as he rose through middle school. She did it in small incremental steps. In about 3rd, maybe late 2nd grade we signed a release to allow him off the bus without us there to get him. His stop was on the same block and allowed him to get home without crossing any streets. The bus driver literally asked me what that release was, as she had never seen it in 6 or 7 years of service. I explained it was to make her life easier not having to deal with us chasing the bus or her having to fill out a report and dump the kid with the police, which is the NYC policy if an adult doesn't pick the kid up.