diff --git a/app/Console/Commands/PruneExportFolders.php b/app/Console/Commands/PruneExportFolders.php
new file mode 100644
index 0000000..9bee72c
--- /dev/null
+++ b/app/Console/Commands/PruneExportFolders.php
@@ -0,0 +1,129 @@
+<?php
+
+namespace App\Console\Commands;
+
+use App\Models\ExportTarget;
+use Illuminate\Console\Command;
+use Illuminate\Support\Carbon;
+
+/**
+ * Empty a handover directory of folders nobody needs any more.
+ *
+ * Only where a destination asks for it — keep_days is null by default, because
+ * a retention rule nobody configured is a deletion nobody expected.
+ *
+ * Safe in a way deleting usually is not: the invoice lives in the database as a
+ * frozen document and its PDF is rendered from that on demand, so anything
+ * removed here can be produced again and re-exported. The directory is a
+ * handover point, not the record.
+ *
+ * Only ever removes folders whose NAME is a date it can parse and that are old
+ * enough. Anything else in there — a stray file, a directory somebody made by
+ * hand, a folder from a different layout — is left alone. A prune that deletes
+ * what it does not recognise is how an archive loses something nobody was
+ * watching.
+ */
+class PruneExportFolders extends Command
+{
+    protected $signature = 'clupilot:prune-exports {--dry-run}';
+
+    protected $description = 'Remove dated folders older than a destination keeps them';
+
+    public function handle(): int
+    {
+        $targets = ExportTarget::query()
+            ->whereNotNull('keep_days')
+            ->where('keep_days', '>', 0)
+            // Only where this machine can see the files. An SFTP destination is
+            // somebody else's disk with somebody else's retention on it.
+            ->where('driver', ExportTarget::LOCAL)
+            ->get();
+
+        foreach ($targets as $target) {
+            $this->prune($target);
+        }
+
+        return self::SUCCESS;
+    }
+
+    private function prune(ExportTarget $target): void
+    {
+        $root = rtrim($target->path, '/');
+
+        if (! is_dir($root)) {
+            // The mount is gone. Saying nothing and doing nothing is right:
+            // this is a cleanup, and a cleanup must never be the thing that
+            // reports a broken mount — nor act on whatever is underneath it.
+            $this->warn("{$target->name}: path is not there, skipping ({$root})");
+
+            return;
+        }
+
+        $cutoff = now()->subDays((int) $target->keep_days)->startOfDay();
+        $removed = 0;
+
+        foreach ((array) scandir($root) as $entry) {
+            if ($entry === '.' || $entry === '..' || ! is_dir($root.'/'.$entry)) {
+                continue;
+            }
+
+            $date = $this->dateFrom($entry);
+
+            // Not a dated folder: left alone, deliberately. A prune that
+            // deletes what it does not recognise is how an archive loses
+            // something nobody was watching.
+            if ($date === null || $date->gte($cutoff)) {
+                continue;
+            }
+
+            if ($this->option('dry-run')) {
+                $this->line("would remove {$root}/{$entry}");
+                $removed++;
+
+                continue;
+            }
+
+            $this->removeTree($root.'/'.$entry);
+            $removed++;
+        }
+
+        $this->line("{$target->name}: {$removed} folder(s) older than {$target->keep_days} days.");
+    }
+
+    /**
+     * Only the exact shapes this application writes.
+     *
+     * Matched with a pattern BEFORE parsing, not by asking Carbon and catching
+     * what it does with nonsense: under strict mode createFromFormat throws
+     * rather than returning false, so a folder somebody made by hand would end
+     * the whole prune instead of being skipped. The pattern also says plainly
+     * which two shapes are recognised, which is the thing a reader wants to
+     * know here.
+     */
+    private function dateFrom(string $name): ?Carbon
+    {
+        if (preg_match('/^(\d{4})-(\d{2})-(\d{2})$/', $name, $m)) {
+            return Carbon::createFromFormat('Y-m-d', $name)?->startOfDay();
+        }
+
+        if (preg_match('/^\d{4}$/', $name)) {
+            return Carbon::createFromFormat('Y-m-d', $name.'-12-31')?->startOfDay();
+        }
+
+        return null;
+    }
+
+    private function removeTree(string $directory): void
+    {
+        foreach ((array) scandir($directory) as $entry) {
+            if ($entry === '.' || $entry === '..') {
+                continue;
+            }
+
+            $path = $directory.'/'.$entry;
+            is_dir($path) ? $this->removeTree($path) : @unlink($path);
+        }
+
+        @rmdir($directory);
+    }
+}
diff --git a/app/Livewire/Admin/EditExportTarget.php b/app/Livewire/Admin/EditExportTarget.php
index 57195b5..ad281a5 100644
--- a/app/Livewire/Admin/EditExportTarget.php
+++ b/app/Livewire/Admin/EditExportTarget.php
@@ -26,6 +26,12 @@ class EditExportTarget extends ModalComponent
 
     public string $path = '';
 
+    /** 'year' for an archive somebody keeps, 'day' for a handover point. */
+    public string $layout = ExportTarget::BY_YEAR;
+
+    /** Empty means keep for ever, which is the default and the safe one. */
+    public ?int $keepDays = null;
+
     public string $host = '';
 
     public ?int $port = 22;
@@ -52,6 +58,8 @@ class EditExportTarget extends ModalComponent
         $this->name = $target->name;
         $this->driver = $target->driver;
         $this->path = $target->path;
+        $this->layout = $target->layout;
+        $this->keepDays = $target->keep_days;
         $this->host = (string) $target->host;
         $this->port = $target->port ?: 22;
         $this->username = (string) $target->username;
@@ -67,6 +75,10 @@ class EditExportTarget extends ModalComponent
             'name' => 'required|string|max:120',
             'driver' => 'required|in:local,sftp',
             'path' => 'required|string|max:255',
+            'layout' => 'required|in:year,day',
+            // Nothing, or a real number of days. Zero would read as "delete
+            // immediately" to somebody who typed it meaning "never".
+            'keepDays' => 'nullable|integer|min:1|max:3650',
             'active' => 'boolean',
         ];
 
@@ -93,6 +105,8 @@ class EditExportTarget extends ModalComponent
             'name' => $data['name'],
             'driver' => $data['driver'],
             'path' => rtrim($data['path'], '/') ?: '/',
+            'layout' => $data['layout'],
+            'keep_days' => $data['keepDays'] ?: null,
             'host' => $this->driver === ExportTarget::SFTP ? $this->host : null,
             'port' => $this->driver === ExportTarget::SFTP ? $this->port : null,
             'username' => $this->driver === ExportTarget::SFTP ? $this->username : null,
diff --git a/app/Models/ExportTarget.php b/app/Models/ExportTarget.php
index 451262f..cf88638 100644
--- a/app/Models/ExportTarget.php
+++ b/app/Models/ExportTarget.php
@@ -22,13 +22,19 @@ class ExportTarget extends Model
 
     public const SFTP = 'sftp';
 
+    /** One folder per year — an archive somebody keeps. */
+    public const BY_YEAR = 'year';
+
+    /** One folder per day — a handover point somebody collects from. */
+    public const BY_DAY = 'day';
+
     protected $fillable = [
-        'name', 'driver', 'path', 'host', 'port', 'username', 'secret_key', 'active',
+        'name', 'driver', 'path', 'layout', 'keep_days', 'host', 'port', 'username', 'secret_key', 'active',
     ];
 
     protected function casts(): array
     {
-        return ['active' => 'boolean', 'port' => 'integer'];
+        return ['active' => 'boolean', 'port' => 'integer', 'keep_days' => 'integer'];
     }
 
     public function exports(): HasMany
@@ -36,6 +42,16 @@ class ExportTarget extends Model
         return $this->hasMany(InvoiceExport::class);
     }
 
+    /** The folder an invoice issued on this date belongs in. */
+    public function folderFor(?\Illuminate\Support\Carbon $issuedOn): string
+    {
+        $date = $issuedOn ?? now();
+
+        return $this->layout === self::BY_DAY
+            ? $date->format('Y-m-d')
+            : $date->format('Y');
+    }
+
     /** Human-readable, for a list and for an error message. */
     public function describe(): string
     {
diff --git a/app/Services/Billing/InvoiceArchive.php b/app/Services/Billing/InvoiceArchive.php
index 40115a3..90dc632 100644
--- a/app/Services/Billing/InvoiceArchive.php
+++ b/app/Services/Billing/InvoiceArchive.php
@@ -51,10 +51,11 @@ final class InvoiceArchive
 
         $disk = $this->disk($target);
 
-        // Grouped by year, because seven years of invoices in one directory is
-        // a directory nobody opens twice.
-        $year = $invoice->issued_on?->format('Y') ?? 'unbekannt';
-        $relative = $year.'/'.$invoice->number.'.pdf';
+        // Per year for an archive somebody keeps, per day for a handover point
+        // somebody collects from — the destination says which, because the two
+        // do different jobs. Either way it is grouped: seven years of invoices
+        // in one directory is a directory nobody opens twice.
+        $relative = $target->folderFor($invoice->issued_on).'/'.$invoice->number.'.pdf';
 
         $pdf = $this->renderer->forInvoice($invoice);
 
diff --git a/database/migrations/2026_07_29_170000_add_layout_and_retention_to_export_targets.php b/database/migrations/2026_07_29_170000_add_layout_and_retention_to_export_targets.php
new file mode 100644
index 0000000..105183e
--- /dev/null
+++ b/database/migrations/2026_07_29_170000_add_layout_and_retention_to_export_targets.php
@@ -0,0 +1,40 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+/**
+ * How a destination is laid out, and how long anything stays there.
+ *
+ * Both per destination, because the two destinations do different jobs. A
+ * handover directory that a NAS collects from wants a folder per day and wants
+ * emptying — thirty days of folders is enough to notice a NAS that stopped
+ * collecting, and keeping more only hides it. The archive on the NAS itself
+ * wants a folder per year and wants nothing deleted, ever.
+ *
+ * Deleting is safe here in a way it usually is not: the invoice lives in the
+ * database as a frozen document and the PDF is rendered from it on demand, so
+ * anything removed from a directory can be produced again. The directory is a
+ * handover point, not the record.
+ *
+ * keep_days NULL means keep for ever, and that is the default: a retention rule
+ * nobody asked for is a deletion nobody expected.
+ */
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::table('export_targets', function (Blueprint $table) {
+            $table->string('layout', 8)->default('year')->after('path');
+            $table->unsignedSmallInteger('keep_days')->nullable()->after('layout');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('export_targets', function (Blueprint $table) {
+            $table->dropColumn(['layout', 'keep_days']);
+        });
+    }
+};
diff --git a/lang/de/finance.php b/lang/de/finance.php
index a2daf44..3eab77e 100644
--- a/lang/de/finance.php
+++ b/lang/de/finance.php
@@ -72,6 +72,12 @@ return [
         'path' => 'Pfad',
         'path_local_hint' => 'Absoluter Pfad. Der Einhängepunkt selbst wird nie angelegt — fehlt er, gilt der Mount als weg und es wird nichts geschrieben.',
         'path_sftp_hint' => 'Verzeichnis auf der Gegenstelle.',
+        'layout' => 'Ordnerstruktur',
+        'layout_year' => 'Ein Ordner je Jahr',
+        'layout_day' => 'Ein Ordner je Tag',
+        'layout_hint' => 'Jahr für ein Archiv, das bleibt. Tag für einen Übergabeort, den jemand abholt.',
+        'keep_days' => 'Aufbewahrung (Tage)',
+        'keep_days_hint' => 'Leer heißt: nichts wird gelöscht. Ein Wert löscht Ordner, die älter sind — ungefährlich, weil jede Rechnung aus der Datenbank neu erzeugt werden kann.',
         'host' => 'Host',
         'port' => 'Port',
         'username' => 'Benutzer',
diff --git a/lang/en/finance.php b/lang/en/finance.php
index 0f1834c..51964a1 100644
--- a/lang/en/finance.php
+++ b/lang/en/finance.php
@@ -72,6 +72,12 @@ return [
         'path' => 'Path',
         'path_local_hint' => 'Absolute path. The mount point itself is never created — if it is missing, the mount counts as gone and nothing is written.',
         'path_sftp_hint' => 'Directory on the far side.',
+        'layout' => 'Folder layout',
+        'layout_year' => 'One folder per year',
+        'layout_day' => 'One folder per day',
+        'layout_hint' => 'Year for an archive that stays. Day for a handover point somebody collects from.',
+        'keep_days' => 'Keep for (days)',
+        'keep_days_hint' => 'Empty means nothing is deleted. A value removes folders older than that — safe, because every invoice can be produced again from the database.',
         'host' => 'Host',
         'port' => 'Port',
         'username' => 'Username',
diff --git a/resources/views/livewire/admin/edit-export-target.blade.php b/resources/views/livewire/admin/edit-export-target.blade.php
index 8861379..f0c0809 100644
--- a/resources/views/livewire/admin/edit-export-target.blade.php
+++ b/resources/views/livewire/admin/edit-export-target.blade.php
@@ -18,6 +18,20 @@
                     :hint="$driver === 'local' ? __('finance.target.path_local_hint') : __('finance.target.path_sftp_hint')"
                     :placeholder="$driver === 'local' ? '/mnt/rechnungen' : '/rechnungen'" />
 
+        <div class="grid gap-4 sm:grid-cols-2">
+            <div>
+                <label class="text-sm font-medium text-body" for="layout">{{ __('finance.target.layout') }}</label>
+                <select id="layout" wire:model="layout"
+                        class="mt-1.5 w-full rounded-md border border-line-strong bg-surface px-3 py-2 text-sm text-body">
+                    <option value="year">{{ __('finance.target.layout_year') }}</option>
+                    <option value="day">{{ __('finance.target.layout_day') }}</option>
+                </select>
+                <p class="mt-1 text-xs text-muted">{{ __('finance.target.layout_hint') }}</p>
+            </div>
+            <x-ui.input name="keepDays" wire:model="keepDays" type="number"
+                        :label="__('finance.target.keep_days')" :hint="__('finance.target.keep_days_hint')" placeholder="30" />
+        </div>
+
         @if ($driver === 'sftp')
             <div class="grid gap-4 sm:grid-cols-3">
                 <div class="sm:col-span-2"><x-ui.input name="host" wire:model="host" :label="__('finance.target.host')" placeholder="backup.example.com" /></div>
diff --git a/routes/console.php b/routes/console.php
index 09d5968..779a7e8 100644
--- a/routes/console.php
+++ b/routes/console.php
@@ -56,3 +56,10 @@ Schedule::call(fn () => \App\Models\StripePendingEvent::query()
 Schedule::command('clupilot:archive-invoices')
     ->hourly()
     ->withoutOverlapping();
+
+// Empty a handover directory of folders past their keep-by. Only where a
+// destination asks for it, and only folders whose name is a date this
+// application wrote — see the command for why it leaves everything else alone.
+Schedule::command('clupilot:prune-exports')
+    ->dailyAt('03:20')
+    ->withoutOverlapping();
diff --git a/tests/Feature/Billing/InvoiceArchiveTest.php b/tests/Feature/Billing/InvoiceArchiveTest.php
index bc1a115..a6facf9 100644
--- a/tests/Feature/Billing/InvoiceArchiveTest.php
+++ b/tests/Feature/Billing/InvoiceArchiveTest.php
@@ -157,3 +157,62 @@ it('sweeps up whatever the queue gave up on', function () {
 
     Queue::assertPushed(ArchiveInvoice::class, 2);
 });
+
+it('puts a handover destination into a folder per day', function () {
+    // A NAS that collects wants today's folder. A folder per year is for an
+    // archive somebody keeps, and the two do different jobs.
+    $this->target->update(['layout' => ExportTarget::BY_DAY]);
+    $invoice = anInvoice();
+
+    (new ArchiveInvoice($invoice, $this->target->refresh()))->handle(app(InvoiceArchive::class));
+
+    expect(is_file($this->archive.'/'.now()->format('Y-m-d').'/'.$invoice->number.'.pdf'))->toBeTrue();
+});
+
+it('removes handover folders past their keep-by, and only those', function () {
+    // Safe in a way deleting usually is not: the invoice is a frozen document
+    // in the database and its PDF is rendered on demand, so anything removed
+    // here can be produced again.
+    $this->target->update(['layout' => ExportTarget::BY_DAY, 'keep_days' => 30]);
+
+    $old = $this->archive.'/'.now()->subDays(40)->format('Y-m-d');
+    $recent = $this->archive.'/'.now()->subDays(3)->format('Y-m-d');
+    $foreign = $this->archive.'/nicht-von-uns';
+
+    foreach ([$old, $recent, $foreign] as $dir) {
+        mkdir($dir, 0o775, true);
+        file_put_contents($dir.'/RE-2026-0001.pdf', 'x');
+    }
+
+    $this->artisan('clupilot:prune-exports')->assertExitCode(0);
+
+    expect(is_dir($old))->toBeFalse()
+        ->and(is_dir($recent))->toBeTrue()
+        // A prune that deletes what it does not recognise is how an archive
+        // loses something nobody was watching.
+        ->and(is_dir($foreign))->toBeTrue();
+});
+
+it('deletes nothing at all where no retention is configured', function () {
+    // The default, and deliberately so: a retention rule nobody asked for is a
+    // deletion nobody expected.
+    $this->target->update(['layout' => ExportTarget::BY_DAY, 'keep_days' => null]);
+
+    $old = $this->archive.'/'.now()->subYears(3)->format('Y-m-d');
+    mkdir($old, 0o775, true);
+
+    $this->artisan('clupilot:prune-exports')->assertExitCode(0);
+
+    expect(is_dir($old))->toBeTrue();
+});
+
+it('does not prune a destination whose mount has gone away', function () {
+    // A cleanup must never be the thing that acts on whatever is underneath an
+    // absent mountpoint.
+    $gone = sys_get_temp_dir().'/clupilot-absent-'.bin2hex(random_bytes(4));
+    $this->target->update(['path' => $gone, 'layout' => ExportTarget::BY_DAY, 'keep_days' => 1]);
+
+    $this->artisan('clupilot:prune-exports')->assertExitCode(0);
+
+    expect(is_dir($gone))->toBeFalse();
+});