diff --git a/Alpha_wrap_3/include/CGAL/Alpha_wrap_3/internal/Alpha_wrap_triangulation_cell_base_3.h b/Alpha_wrap_3/include/CGAL/Alpha_wrap_3/internal/Alpha_wrap_triangulation_cell_base_3.h
index efaeb82d330..cd0c29a99e5 100644
--- a/Alpha_wrap_3/include/CGAL/Alpha_wrap_3/internal/Alpha_wrap_triangulation_cell_base_3.h
+++ b/Alpha_wrap_3/include/CGAL/Alpha_wrap_3/internal/Alpha_wrap_triangulation_cell_base_3.h
@@ -97,7 +97,7 @@ template <typename Cb>
 class Cell_base_with_timestamp
   : public Cb
 {
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 
 public:
   using Has_timestamp = CGAL::Tag_true;
@@ -112,7 +112,7 @@ public:
 public:
   template <typename... Args>
   Cell_base_with_timestamp(const Args&... args)
-    : Cb(args...), time_stamp_(-1)
+    : Cb(args...)
   { }
 
   Cell_base_with_timestamp(const Cell_base_with_timestamp& other)
diff --git a/Mesh_2/include/CGAL/Delaunay_mesh_face_base_2.h b/Mesh_2/include/CGAL/Delaunay_mesh_face_base_2.h
index a3e54124402..46eec90e7e8 100644
--- a/Mesh_2/include/CGAL/Delaunay_mesh_face_base_2.h
+++ b/Mesh_2/include/CGAL/Delaunay_mesh_face_base_2.h
@@ -78,7 +78,7 @@ public:
 
   void set_time_stamp(const std::size_t& ts) { time_stamp_ = ts; }
 
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 };
 
 } // namespace CGAL
diff --git a/Mesh_2/include/CGAL/Delaunay_mesh_vertex_base_2.h b/Mesh_2/include/CGAL/Delaunay_mesh_vertex_base_2.h
index 3093f3b49a9..159a5e77c88 100644
--- a/Mesh_2/include/CGAL/Delaunay_mesh_vertex_base_2.h
+++ b/Mesh_2/include/CGAL/Delaunay_mesh_vertex_base_2.h
@@ -67,7 +67,7 @@ public:
 
   void set_time_stamp(const std::size_t& ts) { time_stamp_ = ts; }
 
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 #endif // CGAL_MESH_2_DEBUG_REFINEMENT_POINTS
 };
 
diff --git a/Mesh_3/include/CGAL/Compact_mesh_cell_base_3.h b/Mesh_3/include/CGAL/Compact_mesh_cell_base_3.h
index 82380d7865b..ecd0236808a 100644
--- a/Mesh_3/include/CGAL/Compact_mesh_cell_base_3.h
+++ b/Mesh_3/include/CGAL/Compact_mesh_cell_base_3.h
@@ -644,7 +644,7 @@ private:
 #ifdef CGAL_INTRUSIVE_LIST
   Cell_handle next_intrusive_ = {}, previous_intrusive_ = {};
 #endif
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 
   std::array<Index, 4> surface_center_index_table_ = {};
   /// Stores visited facets (4 first bits)
diff --git a/Mesh_3/include/CGAL/Mesh_cell_base_3.h b/Mesh_3/include/CGAL/Mesh_cell_base_3.h
index d2f09a0606a..b4552fb048a 100644
--- a/Mesh_3/include/CGAL/Mesh_cell_base_3.h
+++ b/Mesh_3/include/CGAL/Mesh_cell_base_3.h
@@ -273,7 +273,7 @@ private:
 #ifdef CGAL_INTRUSIVE_LIST
   Cell_handle next_intrusive_, previous_intrusive_;
 #endif
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 
 };  // end class Mesh_cell_base_3
 
diff --git a/Mesh_3/include/CGAL/Mesh_polyhedron_3.h b/Mesh_3/include/CGAL/Mesh_polyhedron_3.h
index 454c0c94aff..e6e96d03f03 100644
--- a/Mesh_3/include/CGAL/Mesh_polyhedron_3.h
+++ b/Mesh_3/include/CGAL/Mesh_polyhedron_3.h
@@ -41,7 +41,7 @@ private:
   typedef CGAL::HalfedgeDS_vertex_base<Refs, Tag, Point> Pdv_base;
 
   Set_of_indices indices;
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 
 public:
   int nb_of_feature_edges;
@@ -85,8 +85,8 @@ public:
     return indices;
   }
 
-  Mesh_polyhedron_vertex() : Pdv_base(), time_stamp_(-1), nb_of_feature_edges(0) {}
-  Mesh_polyhedron_vertex(const Point& p) : Pdv_base(p), time_stamp_(-1), nb_of_feature_edges(0) {}
+  Mesh_polyhedron_vertex() : Pdv_base(), nb_of_feature_edges(0) {}
+  Mesh_polyhedron_vertex(const Point& p) : Pdv_base(p), nb_of_feature_edges(0) {}
 };
 
 template <class Refs, class Tprev, class Tvertex, class Tface>
@@ -95,7 +95,7 @@ public CGAL::HalfedgeDS_halfedge_base<Refs,Tprev,Tvertex,Tface>
 {
 private:
   bool feature_edge;
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 
 public:
 
@@ -143,7 +143,7 @@ public CGAL::HalfedgeDS_face_base<Refs,T_,Pln_>
 {
 private:
   Patch_id_ patch_id_;
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 
 public:
 
diff --git a/Mesh_3/include/CGAL/Mesh_vertex_base_3.h b/Mesh_3/include/CGAL/Mesh_vertex_base_3.h
index 46b09094e95..e824f0ba694 100644
--- a/Mesh_3/include/CGAL/Mesh_vertex_base_3.h
+++ b/Mesh_3/include/CGAL/Mesh_vertex_base_3.h
@@ -250,7 +250,7 @@ private:
   Vertex_handle next_intrusive_;
   Vertex_handle previous_intrusive_;
 #endif
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 public:
 
   friend std::istream& operator>>(std::istream &is, Mesh_vertex_3& v)
diff --git a/SMDS_3/include/CGAL/Compact_simplicial_mesh_cell_base_3.h b/SMDS_3/include/CGAL/Compact_simplicial_mesh_cell_base_3.h
index 92272897094..49ac4fcae23 100644
--- a/SMDS_3/include/CGAL/Compact_simplicial_mesh_cell_base_3.h
+++ b/SMDS_3/include/CGAL/Compact_simplicial_mesh_cell_base_3.h
@@ -47,9 +47,7 @@ public:
 
 public:
   // Constructors
-  Compact_simplicial_mesh_cell_3()
-    : time_stamp_(std::size_t(-1))
-  {}
+  Compact_simplicial_mesh_cell_3() {}
 
   Compact_simplicial_mesh_cell_3(const Compact_simplicial_mesh_cell_3& rhs)
     : N(rhs.N)
@@ -279,7 +277,7 @@ private:
   std::array<Cell_handle, 4> N;
   std::array<Vertex_handle, 4> V;
 
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ =  std::size_t(-1);
 
   // The index of the cell of the input complex that contains me
   Subdomain_index subdomain_index_ = {};
diff --git a/SMDS_3/include/CGAL/Simplicial_mesh_cell_base_3.h b/SMDS_3/include/CGAL/Simplicial_mesh_cell_base_3.h
index 8ed8d332f59..7affb29b535 100644
--- a/SMDS_3/include/CGAL/Simplicial_mesh_cell_base_3.h
+++ b/SMDS_3/include/CGAL/Simplicial_mesh_cell_base_3.h
@@ -96,9 +96,7 @@ public:
   };
 
 public:
-  Simplicial_mesh_cell_base_3()
-    : time_stamp_(std::size_t(-1))
-  {}
+  Simplicial_mesh_cell_base_3() {}
 
   Simplicial_mesh_cell_base_3(const Simplicial_mesh_cell_base_3& rhs)
     : Cb(static_cast<const Cb&>(rhs)),
@@ -191,7 +189,7 @@ private:
   /// Stores surface_index for each facet of the cell
   std::array<Surface_patch_index, 4> surface_index_table_ = {};
 
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 
   // The index of the cell of the input complex that contains me
   Subdomain_index subdomain_index_ = {};
diff --git a/SMDS_3/include/CGAL/Simplicial_mesh_vertex_base_3.h b/SMDS_3/include/CGAL/Simplicial_mesh_vertex_base_3.h
index 96a2377355c..6d86764fdca 100644
--- a/SMDS_3/include/CGAL/Simplicial_mesh_vertex_base_3.h
+++ b/SMDS_3/include/CGAL/Simplicial_mesh_vertex_base_3.h
@@ -130,7 +130,6 @@ public:
     , index_()
     , dimension_(-1)
     , cache_validity(false)
-    , time_stamp_(std::size_t(-1))
   {}
 
   // Default copy constructor and assignment operator are ok
@@ -218,7 +217,7 @@ private:
   // that contains me. Negative values are a marker for special vertices.
   short dimension_;
   bool cache_validity;
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 
 public:
   friend std::istream& operator>>(std::istream& is,
diff --git a/STL_Extension/test/STL_Extension/test_Compact_container.cpp b/STL_Extension/test/STL_Extension/test_Compact_container.cpp
index bf6b0d83948..c0235b6f018 100644
--- a/STL_Extension/test/STL_Extension/test_Compact_container.cpp
+++ b/STL_Extension/test/STL_Extension/test_Compact_container.cpp
@@ -18,7 +18,7 @@ template <typename Has_timestamp_ = CGAL::Tag_true>
 struct Node_1
 : public CGAL::Compact_container_base
 {
-  Node_1() {} // // it is important `time_stamp_` is not initialized
+  Node_1() {}
   bool operator==(const Node_1 &) const { return true; }
   bool operator!=(const Node_1 &) const { return false; }
   bool operator< (const Node_1 &) const { return false; }
@@ -49,7 +49,7 @@ struct Node_1
   }
   ///@}
   int m_erase_counter;
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 };
 
 class Node_2
diff --git a/STL_Extension/test/STL_Extension/test_Concurrent_compact_container.cpp b/STL_Extension/test/STL_Extension/test_Concurrent_compact_container.cpp
index a42676f8f7f..b4531b35c5c 100644
--- a/STL_Extension/test/STL_Extension/test_Concurrent_compact_container.cpp
+++ b/STL_Extension/test/STL_Extension/test_Concurrent_compact_container.cpp
@@ -45,7 +45,7 @@ struct Node_1
   void set_time_stamp(const std::size_t& ts) {
     time_stamp_ = ts;
   }
-  std::size_t time_stamp_;
+  std::size_t time_stamp_ = std::size_t(-1);
 };
 
 class Node_2