as long as you have paid your deposit there is no reason to pay until your final payment is due. Put the money aside in a savings account and earn a little interest on it. Credit card definately offers much more protection than cash. Some words of wisdom - don't book a lower grade cabin than what you want and hope for an upgrade,its a crap-shoot at best. Book the best cabin catagory you can afford. A good travel agent will watch the prices and keep you informed.