You can leave that expandable suitcase for another trip because you won't need to take very much with you at all. You'll likely spend a fair bit of time relaxing in a fluffy bathrobe and slippers, but typically these are provided to guests by the resort. If you're planning to go for a splash around in the pool or participate in some relaxing aquatic activities, pack your swimming suit and a spare set of clothes. Loose-fitting garments are ideal. Contemplating taking a fitness class? Bring some sports gear and a pair of comfy trainers. Oh, and don't forget to take your toiletries and other personal items!