Getting travel insurance depends on a lot of factors that include the cost of the cruise to how far in advance you book it.  Certainly, the older you are there is a greater chance that an illness,  unexpected situation can arise before or during any type of vacation.  However,  even younger travelers could experience an accident or sudden illness, fire and other life changing events.  

          Such an event might cause you to cut short your cruise or cause your trip to be canceled altogether.  Since the cruise business works on a small profit margin per person,  most cruise lines impose penalties for canceling a cruise within 60 days of departure, up to and including loss of the entire cruise price.  A few lines penalize for cancellations as much as 90 or 120 days in advance of departure.     If you get a last minute cruise deal you may take the chance and not get the insurance since it would be so close to the cruise date anyway.   But Murphy's Law seems to be par for the course so when you have insurance you can feel assured that you will be covered.    

           IMPORTANT!!!!   Insurance coverage and availability may not apply to people living outside the U.S. and Canada.    So if you do decide on obtaining insurance,  you should check to see what is offered in your country.