For women/girls – bring several styles of swimsuit tops. A week in a halter top can wreak havoc on your neck! Try for strapless or a regular tank top style.
Bring a couple different styles of sunglasses. The backs of my ears and my nose get sore wearing sunglasses all day every day so I like to have one pair with metal frames and nose clips and one pair of tortoise shell style. This will also help with “raccoon eyes” if you don’t have the same shape on your face every day.