We've done two, week-long, riverboat cruises on the Mississippi and Ohio with a group of historical enthusiasts (we've taken up a third of the boat). Consequently, we spend the week in Victorian era attire. The crew loves it and so do most of the other passengers, as well as many of the docents and guides at the historical sites we visit. Some think we're completely nuts and sometimes I agree - wearing a wool 3-peice suit in the muggy hot Mississippi summer can be a trial.
The women bring enough day dresses and ball gowns, plus the associated hats, shoes, and accessories (fans, umbrellas, etc) so that they don't wear anything more than once, and the men bring an assortment of frock coats, military uniforms, and also the associated hats, shoes or boots, etc. The men are a little more fortunate in that they can change a vest and have a completely new look, and often wear one hat with several outfits, but the women can't do that, and of course their dresses take up far more packing space.
Consequently, most of us find that a mere two suitcases per person is quite insufficient. Several couples ship multiple boxes to the boats (imagine a stack of hat boxes 6 feet high!), and I know of one couple that gets two cabins so they could use one for storage of their luggage.
So I love it when I cruise in "modern" attire and only need one or two suitcases!