diff --git a/docs/source/examples/custom_constructors.rst b/docs/source/examples/custom_constructors.rst
index 38f8ce63..dd8605fd 100644
--- a/docs/source/examples/custom_constructors.rst
+++ b/docs/source/examples/custom_constructors.rst
@@ -6,9 +6,9 @@
 Custom constructors
 ===================
 
-:func:`tyro.cli` is designed for comprehensive support of standard Python type
-constructs. In some cases, however, it can be useful to extend the set of types
-supported by :mod:`tyro`.
+:func:`tyro.cli` aims for comprehensive support of standard Python type
+constructs. It can still, however, be useful to extend the set of suported
+types.
 
 We provide two complementary approaches for doing so:
 
@@ -19,6 +19,11 @@ We provide two complementary approaches for doing so:
   instantiated from a single commandline argument, while *struct* types are
   broken down into multiple arguments.
 
+.. warning::
+
+    Custom constructors are useful, but can be verbose and require care. We
+    recommend using them sparingly.
+
 
 .. _example-01_simple_constructors:
 
diff --git a/docs/source/examples/hierarchical_structures.rst b/docs/source/examples/hierarchical_structures.rst
index 9c920f0e..67021bde 100644
--- a/docs/source/examples/hierarchical_structures.rst
+++ b/docs/source/examples/hierarchical_structures.rst
@@ -214,11 +214,11 @@ Structures can be nested inside of standard containers.
         color_tuple: tuple[RGB, RGB]
         color_dict: dict[str, RGB] = dataclasses.field(
             # We can't use mutable values as defaults directly.
-            default_factory={
+            default_factory=lambda: {
                 "red": RGB(255, 0, 0),
                 "green": RGB(0, 255, 0),
                 "blue": RGB(0, 0, 255),
-            }.copy
+            }
         )
 
     if __name__ == "__main__":
diff --git a/docs/source/whats_supported.rst b/docs/source/whats_supported.rst
index fa05cb2b..f579c40a 100644
--- a/docs/source/whats_supported.rst
+++ b/docs/source/whats_supported.rst
@@ -9,7 +9,7 @@ As a partial list, inputs can be annotated with:
 - Basic types like :class:`int`, :class:`str`, :class:`float`, :class:`bool`, :class:`pathlib.Path`, :data:`None`.
 - :class:`datetime.date`, :class:`datetime.datetime`, and :class:`datetime.time`.
 - Container types like :class:`list`, :class:`dict`, :class:`tuple`, and :class:`set`.
-- Union types, like `X | Y`, :py:data:`typing.Union`, and :py:data:`typing.Optional`.
+- Union types, like ``X | Y``, :py:data:`typing.Union`, and :py:data:`typing.Optional`.
 - :py:data:`typing.Literal` and :class:`enum.Enum`.
 - Type aliases, for example using Python 3.12's `PEP 695 <https://peps.python.org/pep-0695/>`_ `type` statement.
 - Generics, such as those annotated with :py:class:`typing.TypeVar` or with the type parameter syntax introduced by Python 3.12's `PEP 695 <https://peps.python.org/pep-0695/>`_.
diff --git a/examples/02_hierarchical_structures/03_nesting_containers.py b/examples/02_hierarchical_structures/03_nesting_containers.py
index 9f3ecd08..1206be99 100644
--- a/examples/02_hierarchical_structures/03_nesting_containers.py
+++ b/examples/02_hierarchical_structures/03_nesting_containers.py
@@ -31,11 +31,11 @@ class Args:
     color_tuple: tuple[RGB, RGB]
     color_dict: dict[str, RGB] = dataclasses.field(
         # We can't use mutable values as defaults directly.
-        default_factory={
+        default_factory=lambda: {
             "red": RGB(255, 0, 0),
             "green": RGB(0, 255, 0),
             "blue": RGB(0, 0, 255),
-        }.copy
+        }
     )
 
 
diff --git a/examples/06_custom_constructors/README.rst b/examples/06_custom_constructors/README.rst
index 23698ee2..277ea3b7 100644
--- a/examples/06_custom_constructors/README.rst
+++ b/examples/06_custom_constructors/README.rst
@@ -1,9 +1,9 @@
 Custom constructors
 ===================
 
-:func:`tyro.cli` is designed for comprehensive support of standard Python type
-constructs. In some cases, however, it can be useful to extend the set of types
-supported by :mod:`tyro`.
+:func:`tyro.cli` aims for comprehensive support of standard Python type
+constructs. It can still, however, be useful to extend the set of suported
+types.
 
 We provide two complementary approaches for doing so:
 
@@ -13,3 +13,8 @@ We provide two complementary approaches for doing so:
   for different types. There are two categories of types: *primitive* types are
   instantiated from a single commandline argument, while *struct* types are
   broken down into multiple arguments.
+
+.. warning::
+
+    Custom constructors are useful, but can be verbose and require care. We
+    recommend using them sparingly.
diff --git a/pyproject.toml b/pyproject.toml
index fffa4ffe..54bf2177 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -10,7 +10,7 @@ name = "tyro"
 authors = [
     {name = "brentyi", email = "brentyi@berkeley.edu"},
 ]
-version = "0.8.14"  # TODO: currently needs to be synchronized manually with __init__.py.
+version = "0.9.0"  # TODO: currently needs to be synchronized manually with __init__.py.
 description = "Strongly typed, zero-effort CLI interfaces"
 readme = "README.md"
 license = { text = "MIT" }
diff --git a/src/tyro/__init__.py b/src/tyro/__init__.py
index 7be6652a..d21704d5 100644
--- a/src/tyro/__init__.py
+++ b/src/tyro/__init__.py
@@ -15,4 +15,4 @@
 
 
 # TODO: this should be synchronized automatically with the pyproject.toml.
-__version__ = "0.8.14"
+__version__ = "0.9.0"