Add me to the list. When I first started cruising - and for the ensuing 10 years or so - I always brought two complete formal outfits, one a tux and the other a dinner jacket. I also brought a dark suit for the "semi-formal" nights. Whoever thought that name up anyway....semi-formal? Kind of stupid when you think about it. It's in the same vein as "smart casual" vs "casual". I never heard of "semi-smart casual" or "casual-formal" but I wouldn't be surprised if they exist.
Anyway, no more tuxedo or dinner jacket for me. I prefer personal comfort as opposed to being trussed up like a stuffed turkey in some silly effort to look elegant. I bring one dark suit, a sport jacket, and two ties. Two button-down shirts. That is my formal wear, with the sport jacket worn with dockers for one of the nights. Otherwise I am in dockers, deck shoes, and either a tropical shirt or polo shirt.