A client sits across from me, or more often these days appears on my screen, and he is excited. He has found the programme, the island, the structure, the house. He has read the brochures and run the numbers for year one, and year one looks magnificent. The tax saving alone pays for the move. The sea view is included.
I let him finish. Then I ask the question I ask in every one of these conversations, and have asked for years:
What does this look like in ten years?
Not next April. Not at the end of the programme's honeymoon period. Ten years. The room usually goes quiet for a moment, and what happens in that quiet is the most valuable part of the consultation.
Why Ten
The number is not arbitrary. I have tried other horizons and they do not work.
Five years is too short. Most bad decisions still look fine at five years. The roof has not started leaking yet. The tax programme is still running. The children are still small enough to move. Five years flatters almost everything.
Twenty years is too long. Nobody can plan twenty years ahead with a straight face, and the attempt produces either paralysis or fantasy. Twenty years ago there was no iPhone. I will not pretend to know what 2046 looks like, and neither should anyone selling you a structure.
Ten years is the useful middle. It is long enough that, on average, the government that made you the promise will have changed, possibly twice. It is long enough for a flagship tax programme to be born, celebrated, abused, criticised in parliament, and abolished. It is long enough for a seven-year-old to become a university applicant, and for your own knees to enter a different phase of life. And it is short enough that you can genuinely reason about it. You know roughly what your family looks like in ten years. You know your own age exactly.
So the test is simple. Take the decision on the table, hold it up against a ten year horizon, and ask what survives. In my experience most of the expensive mistakes I get called in to unwind would have failed this test on day one. Nobody ran it.
Let me walk through where it bites.
The Programme That Will Not Be There
Special tax regimes die. This is not pessimism, it is the observed lifecycle.
Portugal's NHR regime is the cleanest recent example. For years it was the default answer for a certain kind of European mover. Then the political mood turned, and the regime closed to new applicants from January 2024, replaced by the far narrower IFICI, which I have written about separately. Existing holders kept their ten year status, which is worth noting: even in death the programme respected its own decade.
The UK non-dom regime is the bigger corpse. A remittance basis that had existed in some form for over two centuries was abolished with effect from April 2025 and replaced with a four year window for new arrivals. Two hundred years of history bought no protection at all once the politics shifted. I wrote about what that means in practice, but the lesson for our purposes is brutal and simple: if two centuries of precedent cannot carry a regime through one hostile budget, no glossy programme launched in the last five years should be assumed to outlive a decade.
Now apply the test. If your entire relocation case rests on a named programme with a marketing budget, ask what your life in that country looks like the day the programme is repealed for new entrants and grandfathering becomes a political football. If the honest answer is "I would leave", you were never moving to a country. You were moving to a discount, and discounts expire.
Contrast that with what does survive ten years: the deep architecture of a tax system. Territorial taxation of the kind Panama has run for generations is not a programme, it is the constitution of the system, defended by every domestic business elite in the country. The rule of law in Switzerland or Singapore is not a scheme with an application form. Common law courts, property rights, functioning land registries: these things move on a timescale of generations, not budgets. The ten year test does not tell you to avoid attractive regimes. It tells you to check whether the attraction is a poster stuck to the wall or the wall itself.
The House, Honestly Costed
The second place the test bites is property, because property is where year one thinking does the most damage.
Here is the first calculation I make people do. Take the villa at 800,000 euros. The brochure case is the purchase price plus notary fees, and then an imagined future sale at a higher number. My case is different. I use a simple planning assumption of roughly one percent of the property's value per year for maintenance and upkeep, and for older houses, houses by the sea, or houses with pools and gardens I assume more. Salt air eats window frames. Pools eat pumps. Gardens eat gardeners.
So: 8,000 euros a year, call it 80,000 over the decade, and that is the gentle scenario that assumes no new roof, no rewiring, no subsidence, no "the previous owner did this himself". Add insurance, local property taxes, and management if you are not there year round, and a realistic all-in holding cost of 12,000 to 15,000 euros a year is not unusual for a house in that class. Over ten years you are somewhere between 120,000 and 150,000 euros, before a single euro of mortgage interest, and before transaction costs on the way out, which in much of southern Europe are substantial on the way in and taxed on the way out.
Run those numbers against renting something equivalent and investing the difference, and the villa has to appreciate meaningfully just to break even. Sometimes it will. But the point of the test is not that buying is wrong. The point is that the ten year cost of a house is two or three times what the year one buyer has in his head, and he should meet that number before he signs, not in year six when the roof introduces itself. I have made a longer argument about demographics and property elsewhere; here it is enough to say that the decade view turns "the house pays for itself" into a claim that has to survive arithmetic.
The Structure Without Its Builder
The third application is the one my own profession least likes to discuss.
A few years ago a family came to me with a structure built by an adviser who had since retired. It was, in its way, brilliant: a composite of my actual caseload rather than any single client, but the pattern repeats so often it might as well be one man. A holding company in one jurisdiction, an operating company in a second, a foundation in a third, a trust wrapped around part of it, and a set of loan arrangements between the pieces that only made sense if you had been in the room in 2016 when they were set up.
Nobody still working on the file had been in the room in 2016. The annual costs ran to tens of thousands. Filings were being made by people who no longer knew why. And the family's actual circumstances had changed so much that half the machinery was solving problems they no longer had, while creating reporting obligations they very much did have.
So the structural version of the ten year test is this: can this structure be understood, maintained, and if necessary dismantled by a competent professional who has never met its creator? If the answer is no, you do not own a structure. You own a dependency on one person's memory, and people retire, fall ill, and die on schedules that do not consult your holding company. The structures that pass the test are almost always the boring ones: fewer entities, obvious purposes, documentation a stranger could follow. Complexity is not sophistication. Complexity is deferred cost.
Where Are the Children at Eighteen
The fourth application has nothing to do with money, which is why it is skipped most often.
A couple I advised, again a composite, moved when their daughter was seven. At seven, a child is portable. New language, new school, new friends within a term. The move was, for her, close to free. The same family asked me years later about a second move, this time with the daughter at fifteen, and I told them what I tell everyone: the window has closed. At fifteen she has a social world, an academic track, possibly a first love, and a veto she will exercise in ways that can bend the whole project.
The ten year test forces the question early: where is each child at eighteen under this plan? Which country's universities, which language of instruction, which passport, which sense of home? If your seven-year-old will be applying to university from your new country, then you are not choosing a tax residence, you are choosing her formative decade and quite possibly where your grandchildren will grow up. That may be a wonderful choice. It should not be an accidental one. Marriages carry a version of the same question. A move that one spouse experiences as an adventure and the other as an exile does not fail in year one, when everything is new. It fails around year three or four, and by then the structure, the house, and the schooling are all built on top of it.
The Staircase in Chiang Mai
And then there is the application nobody wants to hear from a tax adviser, which is precisely why I insist on it.
I think of it as the staircase test, and I think of a particular kind of house when I do: the beautiful three storey townhouse that a fit sixty-five-year-old buys in Chiang Mai or Lisbon or Tbilisi, bedroom on the top floor, kitchen on the ground floor, and forty steps in between. At sixty-five the staircase is exercise. At seventy-five it is a decision, several times a day. At eighty it is the reason the house gets sold in a hurry, in whatever market happens to exist that year, by children managing it from another continent.
The ten year test applied to your own body is uncomfortable and unavoidable. Whatever your age now, add ten. Then ask about the stairs, yes, but also about the distance to a serious hospital, the availability of specialists in a language you speak, and who exactly comes when something happens at two in the morning. When we chose Davao as a family base in Asia, proximity to real medical care was on the list, not because anyone was ill but because ten years is exactly the horizon on which "nobody is ill" stops being a plan.
What the Test Cannot Do
Now the honest counter-check, because I distrust any framework its own author will not stress test.
The ten year test does not see black swans. It would not have warned you in 2010 about the specific shape of 2020. It cannot price a war, a pandemic, a revolution, or the particular way your industry might be dismantled by a technology that does not exist yet. Anyone claiming a question can filter those events is selling something. That kind of tail risk is what a genuine Plan B is for: second residences, portable assets, optionality held in reserve. The test and the Plan B are complements, not substitutes.
But here is why I use it anyway. Almost none of the expensive failures I actually see are black swans. In my experience, and this is a practitioner's estimate rather than a statistic, something like four out of five of them are entirely foreseeable: the programme that died on schedule, the house whose maintenance was never costed, the structure that outlived its builder's memory, the teenager who refused the second move, the staircase. These are not surprises. They are ten year certainties that were simply never held up to the light, because year one was too exciting.
A filter that catches the foreseeable eighty percent and honestly admits it cannot catch the rest is, in my line of work, about as good as it gets.
So before the next big decision, yours or anyone's, ask the question and sit in the quiet that follows. What does this look like in ten years? If the answer holds, proceed with my blessing. If the answer is a shrug, the shrug is the finding.
Work with Sebastian
If you are weighing a move, a purchase, or a structure and you want someone to run the ten year test on it with you, honestly and before you sign rather than after, that is exactly what a first conversation is for. Book a consultation.
