I usually pack a few more clothing items for a longer stay, and more laundry detergent. I did 3 weeks in the UK with 1 24" spinner case and my DD had the carry on sized one. We had 1 23kg luggage allowance each included in the ticket price. This trip to WDW we will be checking 1 case down, and each taking a carry on bag. I learned to pack light after lugging my Grandparents luggage when I was with them on their last trip to Europe. DD6 did great with th 21" case I have bought her her own one that size (Hey Elsa spinner) to give he packed when we surprise her with this trip!