I meant to buy a flat in my second year here.

Then life had other plans. After a hard stretch I will not lay out in full — climbing out of something, mostly — came a year of just making things stable again, and then a year given over to the language. That last one was not only vocabulary drills: it was the inburgering exams — reading, listening, speaking, and KNM, the Knowledge of Dutch Society paper — the civic-integration set you clear on the way to staying here for good. Suddenly it is the middle of year five, the year residency actually comes into view, the exams close and booked, the language nearly done, and I can feel the capacity opening back up. So it was time to actually look.

Two things pushed me from “someday” to “now.” One was a clear-eyed write-up by fellow expats on what buying in the Netherlands actually involves — the kind of thing that turns fog into a checklist. The other was watching someone I train with go through it in the next lane over. His case is harder than mine, not simpler: he is a zzp’er, and a freelancer’s income is exactly the kind a Dutch lender squints at. Between that, some investments, and a student loan he treats as cheap leverage — money he would rather keep working in the market than rush to repay — he spent two weeks redoing his bookkeeping just so a private-banking consult could tell him whether he would get a mortgage at all, and for how much. Watching someone do the hard part beside you is weirdly motivating.

There is a tempting shortcut here: put your gross salary into the ABN calculator and out comes a number. If you are a straightforward salaried case, that number is most of your answer. My case is not, and I suspect most people’s are not once they actually look. (Patrick McKenzie has quietly rewired how I think about personal finance — treat it as a system you can inspect, not a mood you are in.) The real number is composed of more than salary. It has to include the 30% ruling — the expat tax break that ends for me on a known date in September, quietly taking a chunk of net income with it. It has to include a raise landing next month. It has to include an employee share-purchase plan that pays out a couple of times a year — you buy in at a discount, so a little profit is dependable and the rest rides the market. And it has to include the kosten koper — the cash you need on the table to transact at all, which no affordability calculator ever shows you. There are too many moving parts to hold in your head and still call it honest.

I had done a smaller version of this years ago, in Saint Petersburg. There the Raiffeisen app just showed me the facts, with a clean breakdown of what I spent and decent analytics built right in. The surprise then, and again now, is that spending is mostly stable; you assume your money life is chaos and it mostly is not, you just have not looked at it straight. Here, no Dutch bank gives me anything close to that. If I wanted the picture, I would have to build it.

So I built it. I put my payslips, my income, and my spend into a planning model — good-planning, the swamp extension I built off Bovolon’s framework — and it produced an analysis grounded in facts. It showed me where the money actually goes. It showed me what could be trimmed and what cannot. It showed me what I can genuinely afford, what my cashflow looks like now, in a year, and after the ruling ends in September, and what shapes a mortgage could take around all of it.

The part worth stealing is the model’s structure. The model is a state machine for a decision — Bovolon’s four layers, made queryable. It clarifies what I am assuming, with each assumption tied to a signpost that tells me when it is breaking. It makes explicit what I have actually committed money to — because the real plan is composed of the commitments you have funded and protected, not the boxes on a Gantt chart. It shows how those commitments line up in time. And it contains the part that earns its keep under pressure: a ceiling and a floor. A ceiling is the first place success would bind, with relief pre-cleared before I hit the trigger. A floor is a set of tripwires that fire pre-decided pullbacks, and a maximum loss I have drawn a line at and will not cross. A plan you can only admire tells you the target. A plan you can steer tells you what to do when reality moves.

The benefit I did not expect was quieter than that. Writing the tripwires down externalized the risk, taking it out of my head. The thing that used to circle at one in the morning — what if this, what if that — is now a line in a model with an answer I already decided, calmly, in daylight. I do not re-litigate it every night. I decided it once, and the model holds it for me.

What came out the other end was, in effect, the package you would pay a financial adviser and a mortgage adviser for, and it came out of Claude and the planning skill in an afternoon. The same line from the other piece applies: that analysis is most of what those advisers sell, but the responsibility to manage it is still mine. The model does not carry the consequence home. I carry the consequence home.

The flat is the visible decision. The plan underneath is the real one — the shape I test every apartment against. Knowing my limits before I started looking did not make the choice for me. It just means that when the right place shows up, I will already know whether I can say yes.