Legal Age for Children to Stay Home Alone
It varies by state and it really depends on the level of maturity of the child. Some parenting groups say 12, others will say younger. Here is a site that lists the states and their laws if they even have one. http://www.latchkey-kids.com/latchkey-kids-age-limits.htm
I'm not sure, I started staying home alone since age 9.
It 12 but nine is normal
It all depends whether your kid is named McCaully Culkin or not.
I'm not sure if there is one, it might be subjective - but most kids don't stay home alone until 12 or 13 unless they're exceptionally responsible (and not afraid - that's also a factor).
It depends on how responsible you think the child is