What happens to the argument after we hand it over?

Usually this: it holds for a quarter. Then a page gets written by somebody who never read the architecture, and within a year the company is back to five versions of itself.

The retainer is the arrangement for brands that keep shipping. A fixed amount of implementation work every month, written by the people who wrote the position underneath it.

Up to three implementation deliverables
A landing page, an email sequence, an ad set, a rewritten product page. Three separate things, not three drafts of one thing.
2 revision rounds on each of them
One structural, one line-edit, the same policy as a project. Per deliverable, not two rounds for the whole month.
One call, thirty minutes
At the start of the month, to decide what the three things are. A decision call rather than a status update, and we arrive at it with a recommendation.
Priority scheduling
Retainer work starts within five business days of the month beginning, ahead of the project queue. That is what the arrangement is really buying.
Short answers between the calls
A subject line the team is arguing about, a headline that needs a second opinion, a paragraph a stakeholder has objected to. Answered by email inside the usual two business days, and none of it counts against the three.
The architecture stays current
When the product or the market moves, the pillars get rewritten rather than quietly worked around. This is the part that decays fastest once nobody owns it.
What does not happen
Unused deliverables do not roll into next month. This is a reservation of capacity, not a bank of credits, and the version where they accumulate is how a retainer turns into a debt nobody wants to discuss.

It suits brands publishing something every month with nobody in-house whose actual job is writing. It suits teams who finished a strategy project and now need the same argument said in new places without re-explaining it each time.

It does not suit a one-off need. If what you want is a sales page, buy the sales page copy work; a month of retainer costs more and concentrates less. It also does not suit ten deliverables a month, which is a different arrangement with different economics, and you will hear so rather than be quietly under-served here.

Price
€3,200 a month, invoiced at the start of each month. The published figure is the final amount payable.
Notice
30 days either way, in writing. No annual term and no minimum number of months.
Start date
Whichever month begins after you sign. Nothing is pro-rated mid-month, in either direction, because half a month of three deliverables is not one and a half of anything.
A fourth deliverable
Quoted as a small project, or handled at €85 an hour when it genuinely is small. Heavier monthly scopes get their own number rather than being forced under this one.

Describe a normal month for you and what you would want the three deliverables to be. Within two business days you will hear whether the shape fits and when the next slot actually opens.