Martin, the second part of your question is an important one. Trip cancellation and interruption flight insurance will cover all or a portion of your out-of-pocket expenses, i.e. nonrefundable tickets and deposits and cancellation penalties, should you have to cancel your trip.
See Also: 3 reasons airfares can go up.
However, I always caution people to read the fine print, as the list of exclusions on most standard policies is a mile long. If you have to cancel because of a pre-existing medical condition, or if a family member or pet gets sick, your claim may be denied.
My advice: Protect what you can't lose. If you bought a $100 flight, you do not have a big investment to protect if you should cancel your flight. However, if you bought a $3,000 cruise, consider coverage.
One last caveat: I don't recommend buying travel insurance directly through your travel provider. Buy it from a third party. Otherwise, if your travel provider goes out of business, so could your policy!