Not been on the Destiny but have been on the Celebration which I assume will be the same. You can dress up especially on formal nights but if you want to stay casual you can. You'll mostly seperated & many don't dress up so you wont feel out of place (we didn't dress up). The only other thing is no swimsuits or too revealing outfits in indoor eating or entertainment areas. Talking of entertainment, some from the Celebration team (Bram & Emma) are now on the Destiny & they are excellant.