Other Things We take
I am particular about sweetener, so I took along some stevia.
We also took along a large cup each. The cups on board are usually very small. Mine was a 32 oz coffee cup, and I used it for coffee and iced tea. My wife used a 24 oz cup for tea and flavored water. We would fill these on the buffet and then had what we wanted to drink around the ship.
Ibex Tumbler
One thing to remember when filling a personal cup on the ship, you always use a clean cup from the ship to obtain your beverage and then pour it into your personal cup. Never fill your cup directly from the dispenser.
Another thing we take is zip lock bags. These come in very handy for taking food from the buffet to your room. We used several each day. My wife and I were fond of several things, including dried fruit and pretzel rolls, and we would put them into the bags for those late-night munchies.
They do not have plastic straws on the ship, so if you like plastic straws; take a reusable one with you. You can find a variety of reusable straws on Amazon. I do suggest silicone as if you fall with a metal straw in your mouth, the results could be devastating. Here is a kit that has the straws and a cleaning brush.