Last week on Explorer had to chuckle at all the folks shlepping water, Sprite, iced tea, and such. It's amazing folks can't be satisfied with what the ship offers for a week.
We carry a tiny Eddie Bauer folding bag (fits in pocket) to dinner then get any free drinks we have left as bottles of water for next day. Last week we left 26 drinks + a bottle of wine for our cabin steward.)