Travel and cancellation insurance is always a good idea, as it covers the portion you will NOT receive back!
You or someone in your party may be unable to make the trip or have to leave early for many reasons. You are ensuring not only your vacation but also your total vacation cost. Rates can rise to 6 to 8 % for full coverage deals, and from there. Basic insurance starts at about 3.5% of your total, and Cancel For Any Reason (CFAR) can go up further than that.
During the three months of high hurricane season in the Caribbean (August through October), some vessels may require you to take insurance; otherwise, it’s up to you. If you always get to the airport three hours early, then taking insurance will help your peace of mind.