I think you can find a combination of many things.
Medical knowledge of the
emergency kind is just a good idea since you might be far from no where and need something. In many places
health care is cheaper than in the US but I wouldn't bet that your needs will somehow vanish when you live in paradise.
Good friends came back from 7 years in
South America. They paid cash for a lot of things while out there but now that they are temporarily back they are catching up on a lot of neglected check ups and the consequences that come from it. That's not to say they suffered because they were gone but more that getting older takes it's penalty.
The two most dreaded cruising diseases that can befall you are "grandchildren" number one on the bring you back home list and the worst one of all - "your parents". That can be a problem twice or more if you are married. Some times real life can reach out and grab you by the back of the neck.