diff --git a/apps/backend/src/renovation/furniture.service.ts b/apps/backend/src/renovation/furniture.service.ts
index 309469c..07f20cd 100644
--- a/apps/backend/src/renovation/furniture.service.ts
+++ b/apps/backend/src/renovation/furniture.service.ts
@@ -1120,8 +1120,8 @@ export class FurnitureService {
   }
   private optionValues(dto: CreateFurnitureOptionDto) {
     const text = (value?: string) => value?.trim() || null;
-    const decimal = (value?: number) =>
-      value === undefined ? null : value.toFixed(2);
+    const decimal = (value?: number | null) =>
+      value === undefined || value === null ? null : value.toFixed(2);
     return {
       name: dto.name?.trim() || 'Unbenannter Möbelvorschlag',
       manufacturer: text(dto.manufacturer),
@@ -1130,13 +1130,13 @@ export class FurnitureService {
       retailer: text(dto.retailer),
       productUrl: text(dto.productUrl),
       articleNumber: text(dto.articleNumber),
-      unitPrice: dto.unitPrice.toFixed(2),
+      unitPrice: (dto.unitPrice ?? 0).toFixed(2),
       originalPrice: decimal(dto.originalPrice),
-      shippingCost: dto.shippingCost.toFixed(2),
-      additionalCost: dto.additionalCost.toFixed(2),
-      discount: dto.discount.toFixed(2),
+      shippingCost: (dto.shippingCost ?? 0).toFixed(2),
+      additionalCost: (dto.additionalCost ?? 0).toFixed(2),
+      discount: (dto.discount ?? 0).toFixed(2),
       currency: dto.currency.toUpperCase(),
-      quantity: dto.quantity,
+      quantity: dto.quantity ?? 1,
       width: decimal(dto.width),
       height: decimal(dto.height),
       depth: decimal(dto.depth),
@@ -1154,15 +1154,19 @@ export class FurnitureService {
       budgetCategoryId: dto.budgetCategoryId ?? null,
       existingItem: dto.existingItem,
       estimatedCurrentValue: decimal(dto.estimatedCurrentValue),
-      movingCost: dto.movingCost.toFixed(2),
-      refurbishmentCost: dto.refurbishmentCost.toFixed(2),
+      movingCost: (dto.movingCost ?? 0).toFixed(2),
+      refurbishmentCost: (dto.refurbishmentCost ?? 0).toFixed(2),
       currentLocation: text(dto.currentLocation),
       condition: dto.condition ?? null,
     };
   }
   private total(dto: CreateFurnitureOptionDto) {
     try {
-      return calculateFurnitureTotal(dto);
+      return calculateFurnitureTotal({
+        ...dto,
+        unitPrice: dto.unitPrice ?? 0,
+        quantity: dto.quantity ?? 1,
+      });
     } catch {
       this.validation(
         'Der Rabatt darf die berechneten Gesamtkosten nicht überschreiten.',
diff --git a/apps/frontend/src/app/features/projects/furniture-planning.component.spec.ts b/apps/frontend/src/app/features/projects/furniture-planning.component.spec.ts
index 970e573..c930906 100644
--- a/apps/frontend/src/app/features/projects/furniture-planning.component.spec.ts
+++ b/apps/frontend/src/app/features/projects/furniture-planning.component.spec.ts
@@ -11,10 +11,44 @@ import type {
 } from './hauspilot-api.service';
 import { HauspilotApiService } from './hauspilot-api.service';
 import { FurniturePlanningComponent } from './furniture-planning.component';
+import { ToastService } from '../../shared/ui';
 
 registerLocaleData(localeDe);
 
 describe('FurniturePlanningComponent', () => {
+  it('groups optional furniture details in a collapsed advanced section', async () => {
+    await TestBed.configureTestingModule({
+      imports: [FurniturePlanningComponent],
+      providers: [provideHttpClient()],
+    }).compileComponents();
+    const fixture = TestBed.createComponent(FurniturePlanningComponent);
+    fixture.componentInstance.showOptionForm.set(true);
+    fixture.detectChanges();
+    const host: unknown = fixture.nativeElement;
+    if (!(host instanceof HTMLElement)) throw new Error('Test-Hostelement fehlt.');
+
+    const details = host.querySelector('details.advanced-fields');
+    expect(details?.querySelector('summary')?.textContent).toContain('Erweiterte Informationen');
+    expect(details?.textContent).toContain('Versand');
+    expect(details?.textContent).toContain('Erwartete Lieferung');
+    expect(details?.hasAttribute('open')).toBe(false);
+  });
+
+  it('shows a toast naming a missing required furniture selection', async () => {
+    const show = vi.fn();
+    await TestBed.configureTestingModule({
+      imports: [FurniturePlanningComponent],
+      providers: [provideHttpClient(), { provide: ToastService, useValue: { show } }],
+    }).compileComponents();
+    const component = TestBed.createComponent(FurniturePlanningComponent).componentInstance;
+
+    component.chooseOptionRequirement();
+
+    expect(show).toHaveBeenCalledWith(
+      expect.objectContaining({ message: 'Bitte einen Möbelbedarf auswählen.' }),
+    );
+  });
+
   it('allows optional furniture and delivery fields to stay empty', async () => {
     await TestBed.configureTestingModule({
       imports: [FurniturePlanningComponent],
diff --git a/apps/frontend/src/app/features/projects/furniture-planning.component.ts b/apps/frontend/src/app/features/projects/furniture-planning.component.ts
index fc2af0b..aff26a7 100644
--- a/apps/frontend/src/app/features/projects/furniture-planning.component.ts
+++ b/apps/frontend/src/app/features/projects/furniture-planning.component.ts
@@ -13,6 +13,7 @@ import type {
 import { HauspilotApiService } from './hauspilot-api.service';
 import { conflictMessage } from './project-workspace.helpers';
 import { FurnitureGridComponent } from './furniture-grid.component';
+import { ToastService } from '../../shared/ui';
 
 const categoryLabels: Record<string, string> = {
   seating: 'Sitzmöbel',
@@ -521,40 +522,13 @@ const statusLabels: Record<string, string> = {
               min="0"
               step="0.01"
               formControlName="unitPrice" /></label
-          ><label>Menge<input type="number" min="1" formControlName="quantity" /></label
-          ><label
-            >Versand<input
-              type="number"
-              min="0"
-              step="0.01"
-              formControlName="shippingCost" /></label
-          ><label
-            >Zusatzkosten<input
-              type="number"
-              min="0"
-              step="0.01"
-              formControlName="additionalCost" /></label
-          ><label
-            >Rabatt<input type="number" min="0" step="0.01" formControlName="discount"
-          /></label>
+          ><label>Menge<input type="number" min="1" formControlName="quantity" /></label>
           <output class="calculated"
             >Gesamtpreis:
             <strong>{{
               calculatedTotal() | currency: 'EUR' : 'symbol' : '1.2-2' : 'de'
             }}</strong></output
           >
-          <label>Breite (cm)<input type="number" min="0" formControlName="width" /></label
-          ><label>Höhe (cm)<input type="number" min="0" formControlName="height" /></label
-          ><label>Tiefe (cm)<input type="number" min="0" formControlName="depth" /></label
-          ><label>Farbe<input formControlName="color" /></label
-          ><label>Material<input formControlName="material" /></label
-          ><label
-            >Lieferzeit (Tage)<input type="number" min="0" formControlName="deliveryDays" /></label
-          ><label
-            >Erwartete Lieferung (optional)<input
-              type="date"
-              formControlName="expectedDeliveryDate"
-          /></label>
           <label
             >Verfügbarkeit<select formControlName="availability">
               <option value="unknown">Unbekannt</option>
@@ -578,24 +552,60 @@ const statusLabels: Record<string, string> = {
           ><label class="check"
             ><input type="checkbox" formControlName="existingItem" /> Bereits vorhanden</label
           >
-          @if (optionForm.controls.existingItem.value) {
-            <label
-              >Umzugskosten<input
-                type="number"
-                min="0"
-                step="0.01"
-                formControlName="movingCost" /></label
-            ><label
-              >Aufbereitungskosten<input
-                type="number"
-                min="0"
-                step="0.01"
-                formControlName="refurbishmentCost" /></label
-            ><label>Aktueller Standort<input formControlName="currentLocation" /></label>
-          }
-          <label class="wide"
-            >Beschreibung<textarea rows="3" formControlName="description"></textarea></label
-          ><label class="wide">Notizen<textarea rows="3" formControlName="notes"></textarea></label>
+          <details class="advanced-fields wide">
+            <summary>Erweiterte Informationen</summary>
+            <p class="ui-meta">Diese Angaben sind vollständig optional.</p>
+            <div class="advanced-grid">
+              <label
+                >Versand<input
+                  type="number"
+                  min="0"
+                  step="0.01"
+                  formControlName="shippingCost" /></label
+              ><label
+                >Zusatzkosten<input
+                  type="number"
+                  min="0"
+                  step="0.01"
+                  formControlName="additionalCost" /></label
+              ><label
+                >Rabatt<input type="number" min="0" step="0.01" formControlName="discount"
+              /></label>
+              <label>Breite (cm)<input type="number" min="0" formControlName="width" /></label
+              ><label>Höhe (cm)<input type="number" min="0" formControlName="height" /></label
+              ><label>Tiefe (cm)<input type="number" min="0" formControlName="depth" /></label
+              ><label>Farbe<input formControlName="color" /></label
+              ><label>Material<input formControlName="material" /></label
+              ><label
+                >Lieferzeit (Tage)<input
+                  type="number"
+                  min="0"
+                  formControlName="deliveryDays" /></label
+              ><label
+                >Erwartete Lieferung<input type="date" formControlName="expectedDeliveryDate"
+              /></label>
+              @if (optionForm.controls.existingItem.value) {
+                <label
+                  >Umzugskosten<input
+                    type="number"
+                    min="0"
+                    step="0.01"
+                    formControlName="movingCost" /></label
+                ><label
+                  >Aufbereitungskosten<input
+                    type="number"
+                    min="0"
+                    step="0.01"
+                    formControlName="refurbishmentCost" /></label
+                ><label>Aktueller Standort<input formControlName="currentLocation" /></label>
+              }
+              <label class="wide"
+                >Beschreibung<textarea rows="3" formControlName="description"></textarea></label
+              ><label class="wide"
+                >Notizen<textarea rows="3" formControlName="notes"></textarea>
+              </label>
+            </div>
+          </details>
           <div class="actions">
             <button class="ui-button" type="submit" [disabled]="saving()">Speichern</button
             ><button class="ui-button ui-button--ghost" type="button" (click)="closeOptionForm()">
@@ -1069,6 +1079,21 @@ const statusLabels: Record<string, string> = {
       .calculated {
         align-self: center;
       }
+      .advanced-fields {
+        border: 1px solid var(--color-border);
+        border-radius: var(--radius-md);
+        padding: var(--space-4);
+      }
+      .advanced-fields summary {
+        cursor: pointer;
+        font-weight: var(--font-weight-semibold);
+      }
+      .advanced-grid {
+        display: grid;
+        grid-template-columns: repeat(2, minmax(0, 1fr));
+        gap: var(--space-4);
+        margin-top: var(--space-4);
+      }
       .scenario-grid article {
         border: 1px solid var(--color-border);
         border-radius: var(--radius-md);
@@ -1087,6 +1112,9 @@ const statusLabels: Record<string, string> = {
         text-align: center;
       }
       @media (max-width: 40rem) {
+        .advanced-grid {
+          grid-template-columns: 1fr;
+        }
         .actions .ui-button {
           flex: 1 1 100%;
         }
@@ -1115,6 +1143,7 @@ export class FurniturePlanningComponent implements OnChanges {
   @ViewChild('scenarioDialog') private scenarioDialog?: ElementRef<HTMLDialogElement>;
   @ViewChild('assignmentDialog') private assignmentDialog?: ElementRef<HTMLDialogElement>;
   private readonly api = inject(HauspilotApiService);
+  private readonly toasts = inject(ToastService);
   readonly requirements = signal<FurnitureRequirement[]>([]);
   readonly scenarios = signal<FurnitureScenario[]>([]);
   readonly summary = signal<FurnitureSummary | null>(null);
@@ -1185,24 +1214,19 @@ export class FurniturePlanningComponent implements OnChanges {
     retailer: new FormControl('', { nonNullable: true }),
     productUrl: new FormControl('', { nonNullable: true }),
     articleNumber: new FormControl('', { nonNullable: true }),
-    unitPrice: new FormControl(0, {
-      nonNullable: true,
+    unitPrice: new FormControl<number | null>(null, {
       validators: [(control) => Validators.min(0)(control)],
     }),
-    quantity: new FormControl(1, {
-      nonNullable: true,
+    quantity: new FormControl<number | null>(1, {
       validators: [(control) => Validators.min(1)(control)],
     }),
-    shippingCost: new FormControl(0, {
-      nonNullable: true,
+    shippingCost: new FormControl<number | null>(null, {
       validators: [(control) => Validators.min(0)(control)],
     }),
-    additionalCost: new FormControl(0, {
-      nonNullable: true,
+    additionalCost: new FormControl<number | null>(null, {
       validators: [(control) => Validators.min(0)(control)],
     }),
-    discount: new FormControl(0, {
-      nonNullable: true,
+    discount: new FormControl<number | null>(null, {
       validators: [(control) => Validators.min(0)(control)],
     }),
     width: new FormControl<number | null>(null),
@@ -1251,15 +1275,15 @@ export class FurniturePlanningComponent implements OnChanges {
   });
   readonly calculatedTotal = computed(() => {
     const v = this.optionForm.getRawValue();
-    const acquisition = v.existingItem ? 0 : v.unitPrice * v.quantity;
+    const acquisition = v.existingItem ? 0 : (v.unitPrice ?? 0) * (v.quantity ?? 1);
     return Math.max(
       0,
       acquisition +
-        v.shippingCost +
-        v.additionalCost +
+        (v.shippingCost ?? 0) +
+        (v.additionalCost ?? 0) +
         v.movingCost +
         v.refurbishmentCost -
-        v.discount,
+        (v.discount ?? 0),
     );
   });
   ngOnChanges() {
@@ -1342,7 +1366,11 @@ export class FurniturePlanningComponent implements OnChanges {
     if (!keepFlow) this.guidedPlanning.set(false);
   }
   saveRequirement() {
-    if (this.requirementForm.invalid) return this.requirementForm.markAllAsTouched();
+    if (this.requirementForm.invalid) {
+      this.requirementForm.markAllAsTouched();
+      this.validationToast('Bitte eine gültige Menge und nichtnegative Zahlen eingeben.');
+      return;
+    }
     this.saving.set(true);
     const existing = this.editingRequirement();
     const value = this.requirementForm.getRawValue();
@@ -1381,7 +1409,11 @@ export class FurniturePlanningComponent implements OnChanges {
     if (!keepFlow) this.guidedPlanning.set(false);
   }
   chooseOptionRequirement() {
-    if (this.optionTargetForm.invalid) return this.optionTargetForm.markAllAsTouched();
+    if (this.optionTargetForm.invalid) {
+      this.optionTargetForm.markAllAsTouched();
+      this.validationToast('Bitte einen Möbelbedarf auswählen.');
+      return;
+    }
     const requirement = this.requirements().find(
       (entry) => entry.id === this.optionTargetForm.controls.requirementId.value,
     );
@@ -1400,11 +1432,11 @@ export class FurniturePlanningComponent implements OnChanges {
       retailer: '',
       productUrl: '',
       articleNumber: '',
-      unitPrice: 0,
+      unitPrice: null,
       quantity: r.requiredQuantity,
-      shippingCost: 0,
-      additionalCost: 0,
-      discount: 0,
+      shippingCost: null,
+      additionalCost: null,
+      discount: null,
       width: null,
       height: null,
       depth: null,
@@ -1467,12 +1499,25 @@ export class FurniturePlanningComponent implements OnChanges {
   }
   saveOption() {
     const requirement = this.optionRequirement();
-    if (!requirement || this.optionForm.invalid) return this.optionForm.markAllAsTouched();
+    if (!requirement) {
+      this.validationToast('Bitte zuerst einen Möbelbedarf auswählen.');
+      return;
+    }
+    if (this.optionForm.invalid) {
+      this.optionForm.markAllAsTouched();
+      this.validationToast('Bitte ungültige Preis-, Mengen- oder Maßangaben korrigieren.');
+      return;
+    }
     this.saving.set(true);
     const value = this.optionForm.getRawValue();
     const body = {
       ...value,
       name: value.name.trim() || undefined,
+      unitPrice: value.unitPrice ?? undefined,
+      quantity: value.quantity ?? undefined,
+      shippingCost: value.shippingCost ?? undefined,
+      additionalCost: value.additionalCost ?? undefined,
+      discount: value.discount ?? undefined,
       expectedDeliveryDate: value.expectedDeliveryDate || undefined,
       currency: 'EUR',
     };
@@ -1532,7 +1577,11 @@ export class FurniturePlanningComponent implements OnChanges {
     if (!keepFlow) this.guidedPlanning.set(false);
   }
   createScenario() {
-    if (this.scenarioForm.invalid) return this.scenarioForm.markAllAsTouched();
+    if (this.scenarioForm.invalid) {
+      this.scenarioForm.markAllAsTouched();
+      this.validationToast('Bitte einen Namen für das Szenario eingeben.');
+      return;
+    }
     this.saving.set(true);
     const value = this.scenarioForm.getRawValue();
     this.api
@@ -1631,7 +1680,16 @@ export class FurniturePlanningComponent implements OnChanges {
     this.openOptionPicker();
   }
   saveAssignment() {
-    if (this.assignmentForm.invalid) return this.assignmentForm.markAllAsTouched();
+    if (this.assignmentForm.invalid) {
+      this.assignmentForm.markAllAsTouched();
+      const message = !this.assignmentForm.controls.scenarioId.value
+        ? 'Bitte ein Szenario auswählen.'
+        : !this.assignmentForm.controls.requirementId.value
+          ? 'Bitte einen Möbelbedarf auswählen.'
+          : 'Bitte einen Möbelvorschlag auswählen.';
+      this.validationToast(message);
+      return;
+    }
     const value = this.assignmentForm.getRawValue();
     const scenario = this.scenarios().find((entry) => entry.id === value.scenarioId);
     const requirement = this.requirements().find((entry) => entry.id === value.requirementId);
@@ -1688,6 +1746,13 @@ export class FurniturePlanningComponent implements OnChanges {
         : 'Die Möbelplanung konnte nicht gespeichert werden.';
     this.error.set(conflictMessage(status, fallback));
   }
+  private validationToast(message: string): void {
+    this.toasts.show({
+      tone: 'warning',
+      title: 'Angabe fehlt oder ist ungültig',
+      message,
+    });
+  }
   private openDialog(dialog?: ElementRef<HTMLDialogElement>) {
     queueMicrotask(() => {
       if (dialog && !dialog.nativeElement.open) dialog.nativeElement.showModal();