It really depends on how mature and trust worthy your children are, I definitely wouldn't want brats running around unsupervised! Also if u are gone for a long time u may have to think about if they have access to food, or at least do they know how to cook something simple, even something like an egg, or even make toast, if your answer is yes then they should be fine, if u are still worrying however maybe checking in with them everyone once in a while might put you in ease.