Keep in mind the rooms are small. Formal clothes mean formal shoes, suits, jewelry, etc. My husband & I did formal night. Next time I think I'd skip it and pack warmer clohes leaving NYC in March was very chilly! About 50% of people did. Resort casual is the way to go. If you love to dress up, like me then go for it. But you won't feel out of place if you don't. People really were casual.