You will certainly need one large enough for a change of clothing for yourself and the baby, plus some diapers. The extra things you want to have for a one- or two-day stay will be necessary too. All of these listed bags are the ideal size for this purpose. They are not too large, yet roomy enough to hold the many things you may like to have with you. It is best to buy a larger bag and have it under-packed than to have a smaller bag that will be stuffed and packed too tightly.