Country rankings measure what is easy to measure: cost of living indices, healthcare rankings, English proficiency scores. The factors that actually determine whether someone stays are personal, and they need weighting against your circumstances rather than aggregating into a league table.
The filters, in order
1. Visa eligibility — binary
Either a category fits your situation or it does not. Retiring on savings rules out Japan, Vietnam, South Korea, the Netherlands and Germany, regardless of how much you have. Intending to keep working remotely rules out Spain's non-lucrative visa and Portugal's D7 as commonly understood.
Establish this before anything else. It removes most of the world for most people, which makes the remaining decision far easier.
2. Healthcare, weighted by your age
Under 45 with no conditions, this barely constrains you. Over 60, or with an existing condition, it becomes the dominant factor:
Private insurance becomes markedly more expensive after 60 and difficult to obtain after 70 in many markets. Pre-existing conditions are frequently excluded outright. Public system access usually requires residency, which takes months, leaving a gap. And some countries require insurance as a visa condition — Thailand's O-A visa mandates specified minimum coverage.
Get a quote for your actual age and health before shortlisting anywhere.
3. The after-tax position
Not the cost of living index — your net income in that country, in your circumstances.
Americans should note that zero-tax countries deliver less benefit than expected, because there is no foreign tax to credit against the US liability that follows them. Everyone should check for local taxes with no home equivalent — Spain's wealth tax and asset declaration being the standard surprise.
4. Language, honestly assessed
Not "do they speak English" but "will I learn this, and what happens if I do not".
You can function indefinitely in English in the Netherlands, Dubai, Lisbon and Berlin. You cannot in rural Spain, Italy or Costa Rica, and the countries where a modest budget goes furthest are usually the ones where English is thinnest.
Most countries also require language certification for permanent residency or citizenship, so it becomes compulsory eventually.
5. Community size and stability
A large foreign community makes the first six months much easier and the second year harder, because it turns over constantly.
The most settled outcomes tend to come from medium-sized communities in places where some local integration is necessary — enough English speakers to land softly, enough friction to push you outward.
6. Climate, in the worst month
Everywhere is pleasant in its best season. What matters is the other one.
Chiang Mai's burning season from February to April pushes air quality to genuinely unhealthy levels and drives people out annually. Dubai from June to September exceeds 45°C and life moves indoors. Portuguese and Spanish houses are frequently unheated and winter is colder inside than visitors expect. Coastal Costa Rica and much of Southeast Asia have wet seasons that close businesses.
The research that is actually worth doing
Visit in the worst month, for a month. A week in the good season tells you nothing you did not already assume. Four weeks in the difficult season tells you almost everything.
Rent short, twice. Two or three months in each of two candidate places beats any amount of reading.
Price your actual insurance. Not an average — a quote for your age and history.
Talk to people who left. Expat forums are full of arrivals and enthusiasts. The people who tried it and went home have the information that is missing from every ranking, and they are usually happy to explain why.
The framework in one line
Visa eligibility, then healthcare for your age, then after-tax income, then language, then community, then climate — and visit in the worst month before committing to any of it.