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To a point, I agree with your husband about continuing to spend for the sake of just giving them a box to open for Christmas. If they aren't REALLY in need of some of the things you are thinking of--swimsuits, sunglasses, etc., don't buy them. (You will probably end up spending more than you expect by the time the vacation is over anyway, so save the money you will be spending for the actual vacation)
But as someone else suggested, building the suspense is a fun idea. Maybe give gifts that relate but aren't too expensive--sunscreen, a beach related movie, cheap sunglasses/leis/grass skirts from the dollar store, disposable cameras, etc.
2 years ago on Mike & Liza's Marriage Ref: Cruise Scrooge