When our girls were 8 and 7, they had fanny packs with a few snack, hand sanitizer, a card with info in case they got lost, etc. The fanny packs worked great because they had their hands free, couldn't really lose them, and carried enough to have a snack without opening the big backpack and digging through. Last year when we went, they were 11 and 10, and they each had a small backpack with the same stuff + a water bottle, jacket if they weren't wearing it, camera, etc. I think it is great for kids to have their own little bag or fanny pack once they are old enough. It's good to have something that stays on easily with their hands free.