We are taking our first cruise a western Carribean from New Orleans in September. Carnival and our travel agent say we only need birth cert. and pic ID's, but everyone I have talked to that has taken a cruise says we should get the passports. There are 5 of us traveling and I don't know if we will ever have occasion to use them again, so what do you experts think, should we bite the bullet and spend the $$$$ for 5 passports or just use what we have? Thanks for any advice.