Well I've raised 2 girls well into their teens and my youngest just entered tweendom and I've never heard of/considered an emergency bag. Pretty much beginning in middle school my girls started to use purses for phones, chapstick, money, etc. in addition to the backpacks/bags for their books/lunch. They just stuff a handful of pads in their purse and call it a day! My 16yo also has a small bottle of Tylenol (and a signed release allowing her to self-administer) for when she gets cramps during school.