Yes, anytime you leave the country you do.
Yes, you need a valid passport to travel to Australia.
If you are form Australia than no need to passport to travel < a href=http://www.cruiseeasy.com.au/>cruise Australia.
If you are a US citizen, you will need both a valid US passport and an Australian ETA visa to travel to Australia.
Yes, a US passport holder needs a visa to travel to Australia.
Yes you do.
No. Passports are for international travel.
Yes
No, but you do need a valid passport.
You'll need a US PASSPORT to return to the US.
No. The only time a passport is required is when you are leaving U.S. borders.
If you are a United States citizen, you do not need a passport to travel from NY to California, as these are both part of the U.S. If you are not a United States citizen, you should have your passport from your home country with you whenever you travel in the U.S.
No, you do not need a passport to enter California if you are a U.S. citizen traveling within the country. However, if you are coming from outside the U.S., you will need a valid passport and possibly a visa, depending on your nationality. Always check the latest travel requirements before your trip.