This is probably my g-g-generation, but good heavens, they're 8 and 12! - I don't think I was ever literally a latch-key kid, because my mother (when my little brother was old enough to go to school himself) got a job in a school with school-friendly hours, but it was certainly A Thing in those days then. But at that age, do they need Mommy hanging over them all the time? They might reasonably manage not to fall into the fire or put beans up their noses if left to their own devices.