Wife packs a bag with snacks, sunscreen, cups for above mentioned hidden beverages, first aid kit, and a few other things you will decide you needed after the first time. Then we throw in chairs and a couple of blankets. The cooler is loaded with more than we ever expect to drink just in case.
From the AC perspective I carry a backpack with an iPad, line up cards, pens/pencils, sunscreen, towel, multi tool, and helmet hardware kits. I was surprised to see how many times I had to change out a clip on a face mask or catchers helmet. I didn't carry it but one other assistant had a glove lacing kit for emergencies which we used several times.
From the AC perspective I carry a backpack with an iPad, line up cards, pens/pencils, sunscreen, towel, multi tool, and helmet hardware kits. I was surprised to see how many times I had to change out a clip on a face mask or catchers helmet. I didn't carry it but one other assistant had a glove lacing kit for emergencies which we used several times.