diff --git a/Cargo.toml b/Cargo.toml
index 5992d0a9e..3074e9cfa 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -51,7 +51,8 @@ kv_sval = ["kv", "value-bag/sval", "sval", "sval_ref"]
 kv_std = ["std", "kv", "value-bag/error"]
 kv_serde = ["kv_std", "value-bag/serde", "serde"]
 
-# Legacy: use `kv_*` instead
+# Deprecated: use `kv_*` instead
+# These `*_unstable` features will be removed in a future release
 kv_unstable = ["kv"]
 kv_unstable_sval = ["kv_sval"]
 kv_unstable_std = ["kv_std"]
diff --git a/src/kv/mod.rs b/src/kv/mod.rs
index 44f7b06df..6dbfe6f66 100644
--- a/src/kv/mod.rs
+++ b/src/kv/mod.rs
@@ -236,10 +236,21 @@
 
 mod error;
 mod key;
+
+#[cfg(not(feature = "kv_unstable"))]
 mod source;
+#[cfg(not(feature = "kv_unstable"))]
 mod value;
 
 pub use self::error::Error;
 pub use self::key::{Key, ToKey};
 pub use self::source::{Source, VisitSource};
 pub use self::value::{ToValue, Value, VisitValue};
+
+#[cfg(feature = "kv_unstable")]
+pub mod source;
+#[cfg(feature = "kv_unstable")]
+pub mod value;
+
+#[cfg(feature = "kv_unstable")]
+pub use self::source::Visitor;
diff --git a/src/kv/source.rs b/src/kv/source.rs
index 33d5a1a73..0ca267ce3 100644
--- a/src/kv/source.rs
+++ b/src/kv/source.rs
@@ -458,6 +458,10 @@ mod std_support {
     }
 }
 
+// NOTE: Deprecated; but aliases can't carry this attribute
+#[cfg(feature = "kv_unstable")]
+pub use VisitSource as Visitor;
+
 #[cfg(test)]
 mod tests {
     use crate::kv::value;
diff --git a/src/kv/value.rs b/src/kv/value.rs
index 6bfff4e4e..96cb411d1 100644
--- a/src/kv/value.rs
+++ b/src/kv/value.rs
@@ -298,6 +298,12 @@ macro_rules! impl_to_value_primitive {
                     Value::from_inner(value)
                 }
             }
+
+            impl<'v> From<&'v $into_ty> for Value<'v> {
+                fn from(value: &'v $into_ty) -> Self {
+                    Value::from_inner(*value)
+                }
+            }
         )*
     };
 }
@@ -316,6 +322,12 @@ macro_rules! impl_to_value_nonzero_primitive {
                     Value::from(value.get())
                 }
             }
+
+            impl<'v> From<&'v std::num::$into_ty> for Value<'v> {
+                fn from(value: &'v std::num::$into_ty) -> Self {
+                    Value::from(value.get())
+                }
+            }
         )*
     };
 }
@@ -1034,6 +1046,130 @@ pub(in crate::kv) mod inner {
     }
 }
 
+impl<'v> Value<'v> {
+    /// Get a value from a type implementing `std::fmt::Debug`.
+    #[cfg(feature = "kv_unstable")]
+    #[deprecated(note = "use `from_debug` instead")]
+    pub fn capture_debug<T>(value: &'v T) -> Self
+    where
+        T: fmt::Debug + 'static,
+    {
+        Value::from_debug(value)
+    }
+
+    /// Get a value from a type implementing `std::fmt::Display`.
+    #[cfg(feature = "kv_unstable")]
+    #[deprecated(note = "use `from_display` instead")]
+    pub fn capture_display<T>(value: &'v T) -> Self
+    where
+        T: fmt::Display + 'static,
+    {
+        Value::from_display(value)
+    }
+
+    /// Get a value from an error.
+    #[cfg(feature = "kv_unstable_std")]
+    #[deprecated(note = "use `from_dyn_error` instead")]
+    pub fn capture_error<T>(err: &'v T) -> Self
+    where
+        T: std::error::Error + 'static,
+    {
+        Value::from_dyn_error(err)
+    }
+
+    /// Get a value from a type implementing `serde::Serialize`.
+    #[cfg(feature = "kv_unstable_serde")]
+    #[deprecated(note = "use `from_serde` instead")]
+    pub fn capture_serde<T>(value: &'v T) -> Self
+    where
+        T: serde::Serialize + 'static,
+    {
+        Value::from_serde(value)
+    }
+
+    /// Get a value from a type implementing `sval::Value`.
+    #[cfg(feature = "kv_unstable_sval")]
+    #[deprecated(note = "use `from_sval` instead")]
+    pub fn capture_sval<T>(value: &'v T) -> Self
+    where
+        T: sval::Value + 'static,
+    {
+        Value::from_sval(value)
+    }
+
+    /// Check whether this value can be downcast to `T`.
+    #[cfg(feature = "kv_unstable")]
+    #[deprecated(
+        note = "downcasting has been removed; log an issue at https://github.com/rust-lang/log/issues if this is something you rely on"
+    )]
+    pub fn is<T: 'static>(&self) -> bool {
+        false
+    }
+
+    /// Try downcast this value to `T`.
+    #[cfg(feature = "kv_unstable")]
+    #[deprecated(
+        note = "downcasting has been removed; log an issue at https://github.com/rust-lang/log/issues if this is something you rely on"
+    )]
+    pub fn downcast_ref<T: 'static>(&self) -> Option<&T> {
+        None
+    }
+}
+
+// NOTE: Deprecated; but aliases can't carry this attribute
+#[cfg(feature = "kv_unstable")]
+pub use VisitValue as Visitor;
+
+/// Get a value from a type implementing `std::fmt::Debug`.
+#[cfg(feature = "kv_unstable")]
+#[deprecated(note = "use the `key:? = value` macro syntax instead")]
+#[macro_export]
+macro_rules! as_debug {
+    ($capture:expr) => {
+        $crate::kv::Value::from_debug(&$capture)
+    };
+}
+
+/// Get a value from a type implementing `std::fmt::Display`.
+#[cfg(feature = "kv_unstable")]
+#[deprecated(note = "use the `key:% = value` macro syntax instead")]
+#[macro_export]
+macro_rules! as_display {
+    ($capture:expr) => {
+        $crate::kv::Value::from_display(&$capture)
+    };
+}
+
+/// Get a value from an error.
+#[cfg(feature = "kv_unstable_std")]
+#[deprecated(note = "use the `key:error = value` macro syntax instead")]
+#[macro_export]
+macro_rules! as_error {
+    ($capture:expr) => {
+        $crate::kv::Value::from_dyn_error(&$capture)
+    };
+}
+
+#[cfg(feature = "kv_unstable_serde")]
+#[deprecated(note = "use the `key:serde = value` macro syntax instead")]
+/// Get a value from a type implementing `serde::Serialize`.
+#[macro_export]
+macro_rules! as_serde {
+    ($capture:expr) => {
+        $crate::kv::Value::from_serde(&$capture)
+    };
+}
+
+/// Get a value from a type implementing `sval::Value`.
+#[cfg(feature = "kv_unstable_sval")]
+#[deprecated(note = "use the `key:sval = value` macro syntax instead")]
+#[macro_export]
+macro_rules! as_sval {
+    ($capture:expr) => {
+        $crate::kv::Value::from_sval(&$capture)
+    };
+}
+
 #[cfg(test)]
 pub(crate) mod tests {
     use super::*;