diff --git a/include/pybind11/pybind11.h b/include/pybind11/pybind11.h
index 82c5423de..6fe93e0ae 100644
--- a/include/pybind11/pybind11.h
+++ b/include/pybind11/pybind11.h
@@ -1797,8 +1797,14 @@ struct property_cpp_function<
 
 #endif // PYBIND11_HAVE_INTERNALS_WITH_SMART_HOLDER_SUPPORT
 
+#ifdef PYBIND11_USE_SMART_HOLDER_AS_DEFAULT
+// BAKEIN_WIP: Add comment to explain: This is meant for stress-testing only.
 template <typename>
 using default_holder_type = pybindit::memory::smart_holder;
+#else
+template <typename T>
+using default_holder_type = std::unique_ptr<T>;
+#endif
 
 template <typename type_, typename... options>
 class class_ : public detail::generic_type {
@@ -1816,8 +1822,7 @@ public:
     using type = type_;
     using type_alias = detail::exactly_one_t<is_subtype, void, options...>;
     constexpr static bool has_alias = !std::is_void<type_alias>::value;
-    using holder_type
-        = detail::exactly_one_t<is_holder, pybindit::memory::smart_holder, options...>;
+    using holder_type = detail::exactly_one_t<is_holder, default_holder_type<type>, options...>;
 
     static_assert(detail::all_of<is_valid_class_option<options>...>::value,
                   "Unknown/invalid class_ template parameters provided");
diff --git a/include/pybind11/smart_holder.h b/include/pybind11/smart_holder.h
index d2aac88e8..8735ca95d 100644
--- a/include/pybind11/smart_holder.h
+++ b/include/pybind11/smart_holder.h
@@ -13,10 +13,12 @@
 
 PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
+// Supports easier switching between py::class_<T> and py::class_<T, py::smart_holder>:
+// users can simply replace the `_` in `class_` with `h` or vice versa.
 template <typename type_, typename... options>
-class classh : public class_<type_, options...> {
+class classh : public class_<type_, pybindit::memory::smart_holder, options...> {
 public:
-    using class_<type_, options...>::class_;
+    using class_<type_, pybindit::memory::smart_holder, options...>::class_;
 };
 
 PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/tests/test_class.cpp b/tests/test_class.cpp
index ba462fa85..2701632e1 100644
--- a/tests/test_class.cpp
+++ b/tests/test_class.cpp
@@ -614,8 +614,13 @@ CHECK_NOALIAS(8);
 CHECK_HOLDER(1, unique);
 CHECK_HOLDER(2, unique);
 CHECK_HOLDER(3, unique);
+#ifdef PYBIND11_USE_SMART_HOLDER_AS_DEFAULT
 CHECK_SMART_HOLDER(4);
 CHECK_SMART_HOLDER(5);
+#else
+CHECK_HOLDER(4, unique);
+CHECK_HOLDER(5, unique);
+#endif
 CHECK_HOLDER(6, shared);
 CHECK_HOLDER(7, shared);
 CHECK_HOLDER(8, shared);