It is surprisingly common for Americans to think all they have to do is pick any retirement country they like, and then armed with their US passport, airline ticket, and a charged-up ATM card, they can move there permanently.
Sorry, it ain't so.
In truth, that is generally the way it is for travelling to many foreign nations because a US passport is a convenient passport to hold for traveling, but actually moving to a foreign country is an entirely different matter. Foreign governments have pretty specific policies on what they need to see to allow people to stay permanently (or semi-permanently). Some countries such as Canada don't offer any kind of visa option at all for retired foreigners.
These requirements are usually, but not exclusively about things like age, finances, and health status. For example, country X may need you to be 50 to get a retirement visa, or country Y may not allow you unless you can show a pension or social security income stream of a certain minimum amount. Each country is different, naturally.
So if a country strikes your fancy, the first thing you need to do is find out about what is required to qualify for a visa that would allow you to live there. If you can't exactly meet all their requirements, the next step after that is to ask yourself how badly you need to live in that country, and then you can explore some of the possible loopholes more deeply. For example, maybe an immigration lawyer in the host country could come up with some kind of scenario that would allow you to stay. Or perhaps it is one of those countries where you can stay for years or decades as a permanent "tourist" which usually involves periodic border runs (happy happy joy joy).
Otherwise, its best to move on and look for a country choice that can actually be a reality for you.
RetireAway's Retirement Country Profiles provide some basic long stay visa possibilities for many countries. Some countries are officially more welcoming to retired people than others.
Post your comments and questions about this topic to the following RetireAway Discussion Forums:
Americans Retiring Abroad,
Retirement Countries,
Money Matters,
or any other appropriate
RetireAway Discussion Forum.