It is always a good idea if you have more than one suitcase to spread clothing around.
My first cruise was on the MS Mermoz, run by Paquet, a French cruise line, out of Miami. They had two ships leaving the same day, and a woman in our group NEVER got her bag. She only had one bag. The bag got delivered to the wrong ship, and despite the cruise line allegedly searching "everywhere" they apparently never radioed the other ship to check, and the crew on the other ship never thought it might belong to someone on the other ship. The cruise line assummed it was the airlines fault (the airline was Pan Am), and reluctantly gave her $200 store credit on board to buy clothing. It was a business trip, so our boss told her to buy what she needed (including a new suitcase) and we'd figure it out after the cruise. At the end of the cruise, Paquet finally did agree to pick up the tab for all the clothes when it was clear it was there mistake.
Very odd, because otherwise, I have never been on a cruise with such a high level of on board customer service. Yes, even higher than Disney. Even the wine was included in the price of the cruise. But they just didn't seem prepared to deal with missing luggage.