How much you carry depends on whether you like to be ultra-prepared or to travel light. If you're bottle-feeding, you're going to want to keep extra bottles, nipples and formula in the bag. Are you a nursing mom? Throw in your nursing cover. Be sure to have important numbers (in case of an emergency), extra money (you'll be prepared for an unexpected snack time), a hat, zip-top bags (for dirty diapers or clothes), an extra blanket and a change of clothes, since you never know when there will be a diaper blowout! Another smart idea: Keep a copy of baby's updated immunization card in a safe spot (like a plastic baggie, so it won't get spilled on!) so you're prepared at each doctor's visit. Of course, don't forget wipes and extra diapers (one for every two hours, plus a few extra)!