We are going to Australia and New Zealand next year and I need to know whether its a good idea and/or necessary to exchange US dollars for Australian dollars and New Zealand dollars? Will I need Aussie dollars for the taxi cab from the airport to the hotel; for shopping for souvenirs from a market, or small store; for tipping; and for things we may buy from a street vendor?? Then if I buy Aussie dollars will they be any good (accepted) in New Zealand for the same type activities (i.e. taxi, small purchases) or will I need some of both currencies ??