No idea - in each case it depends on when I think they are mature enough to cope. Since different children mature at different times I'm not prepared to take a guess on when mine will be old enough. It also depends on where we are - walking to school in a small town or close-knit community on quiet streets is not the same as walking by a busy road or in a rough neighbourhood.

At the moment my children are playing unsupervised but the second they go quiet or start making excessive noises I will check on them - is that being left to their own devices?