I left a baby, a seven-year-old and an extremely mature eleven-year-old alone under very limited circumstances, infrequently. Then, when they were a little older, I left a toddler, an eight-year-old and a very mature 12-year-old alone. Still under very specific circumstances. More usual to arrange for a nearby neighbor to babysit.
Things may work out if you know what your kids are like... Even if you make sure the eldest is "legal" to stay home alone, so much depends upon your particular kids. And even if you think all your ducks are in a row, there's always the unforseen emergency. They really need telephone access to you, and immediate access to a trusted neighbor, in case something happens they are unequal to dealing with.
Some adults fall apart in emergencies, you know. We expect a lot of our kids. Sure, there are very very young children caring for younger siblings over in lands ravaged by war and famine and disease, and thank God for them. But when we hear the sad yet heroic tales of these youngsters, we don't usually hear about all their little cousins and neighbors who have not survived the emergency.