My tuxedo is too big for me now and hasn't been out of the closet in four years. Most of my wife's formal dresses have gone to Goodwill.
I now take one sports jacket and a couple of dress shirts, one pair of dress slacks and one or two ties when we cruise on a traditional cruise. I do have a dark suit that I will use if I sail a truly formal ship. On other nights it's a Polo shirt, button up shirt and a pair of Docker type pants.
We really try to book open seating and Freestyle type cruises. We will be sailing on Royal Caribbean next month so I guess the dark will need to come with or I may just use the sports jacket for formal night and the alternative restaurants.
My wife likes to "dress nice" but she does not like the "formal" evenings and it got to a point where she didn't want to cruise if it required buying, packing and wearing formal wear and all that goes with it. Women have it much harder than men.