diff --git a/cmd/metal-api/internal/metal/size.go b/cmd/metal-api/internal/metal/size.go
index 62b4a194d..8d0f3852a 100644
--- a/cmd/metal-api/internal/metal/size.go
+++ b/cmd/metal-api/internal/metal/size.go
@@ -142,10 +142,8 @@ func (s *Size) Validate(partitions PartitionMap, projects map[string]*mdmv1.Proj
 		}
 	}
 
-	if s.Reservations != nil {
-		if err := s.Reservations.Validate(partitions, projects); err != nil {
-			return fmt.Errorf("invalid size reservation: %w", err)
-		}
+	if err := s.Reservations.Validate(partitions, projects); err != nil {
+		return fmt.Errorf("invalid size reservation: %w", err)
 	}
 
 	return nil
@@ -162,30 +160,44 @@ func (s *Size) Overlaps(ss *Sizes) *Size {
 	return nil
 }
 
-func (rs Reservations) ForPartition(partitionID string) Reservations {
+func (rs *Reservations) ForPartition(partitionID string) Reservations {
+	if rs == nil {
+		return nil
+	}
+
 	var result Reservations
-	for _, r := range rs {
+	for _, r := range *rs {
 		r := r
 		if slices.Contains(r.PartitionIDs, partitionID) {
 			result = append(result, r)
 		}
 	}
+
 	return result
 }
 
-func (rs Reservations) ForProject(projectID string) Reservations {
+func (rs *Reservations) ForProject(projectID string) Reservations {
+	if rs == nil {
+		return nil
+	}
+
 	var result Reservations
-	for _, r := range rs {
+	for _, r := range *rs {
 		r := r
 		if r.ProjectID == projectID {
 			result = append(result, r)
 		}
 	}
+
 	return result
 }
 
-func (rs Reservations) Validate(partitions PartitionMap, projects map[string]*mdmv1.Project) error {
-	for _, r := range rs {
+func (rs *Reservations) Validate(partitions PartitionMap, projects map[string]*mdmv1.Project) error {
+	if rs == nil {
+		return nil
+	}
+
+	for _, r := range *rs {
 		if r.Amount <= 0 {
 			return fmt.Errorf("amount must be a positive integer")
 		}
diff --git a/cmd/metal-api/internal/service/partition-service.go b/cmd/metal-api/internal/service/partition-service.go
index 5fd1c7398..615dc95b8 100644
--- a/cmd/metal-api/internal/service/partition-service.go
+++ b/cmd/metal-api/internal/service/partition-service.go
@@ -457,13 +457,11 @@ func (r *partitionResource) calcPartitionCapacity(pcr *v1.PartitionCapacityReque
 
 			size := sizesByID[cap.Size]
 
-			if size.Reservations != nil {
-				for _, reservation := range size.Reservations.ForPartition(pc.ID) {
-					reservation := reservation
+			for _, reservation := range size.Reservations.ForPartition(pc.ID) {
+				reservation := reservation
 
-					cap.Reservations += reservation.Amount
-					cap.UsedReservations += min(len(machinesByProject[reservation.ProjectID]), reservation.Amount)
-				}
+				cap.Reservations += reservation.Amount
+				cap.UsedReservations += min(len(machinesByProject[reservation.ProjectID]), reservation.Amount)
 			}
 		}
 
diff --git a/cmd/metal-api/internal/service/project-service.go b/cmd/metal-api/internal/service/project-service.go
index 36edec520..8116d7a88 100644
--- a/cmd/metal-api/internal/service/project-service.go
+++ b/cmd/metal-api/internal/service/project-service.go
@@ -255,9 +255,7 @@ func (r *projectResource) deleteProject(request *restful.Request, response *rest
 	for _, size := range sizes {
 		size := size
 
-		if size.Reservations != nil {
-			sizeReservations = size.Reservations.ForProject(id)
-		}
+		sizeReservations = size.Reservations.ForProject(id)
 	}
 
 	if len(sizeReservations) > 0 {