This is often a very underestimated point. In the last 25 years, we have seen many incidents on islands, where the availability of medical services was vital. Many clients believe that they are healthy and nothing bad can happen. However, accidents may occur like a falling coconut, or someone may have an unexpected health issue like a heart attack! Whatever it is, it can effect the owner, his/her family, friends or employees (in certain circumstances, the owner may be liable).
Personally, I would never buy an island unless it is possible to be transported from the island to a hospital within one hour. We could stretch this to possibly 90 minutes but that should be the very maximum. You should not consider buying an island if you cannot get to a hospital, clinic or medical service station within a maximum of 90 minutes. Even if you take the risk and buy a remote island, if you decide to sell the island, the new buyer may be more concerned about the proximity of medical services and decide against buying the island. These islands will then be worth less.
The 90 minutes requirement can be fulfilled easily – especially if emergency helicopters can access the island in that area.
This point is one of the reasons why so many islands are left undeveloped in certain countries and areas. Very likely, they will never be developed. Most islands, where medical services are nearby, are developed and are accordingly higher valued.
In the whole island world, this is, in the end, the most crucial point. Unfortunately, some island owners have lost their lives, as they did not consider the importance of the availability of medical services nearby.
Since islands, where medical services are close by, are the only types considered by users, these islands are good investments.
Please note that the requirement of medical services nearby may not apply to resort and hotel islands, as these islands often have first-aid staff and clinics on the island. They are often well-prepared for emergency situations.