diff --git a/slog/benchmarks/benchmarks_test.go b/slog/benchmarks/benchmarks_test.go
index ce8262005..8cea9fa20 100644
--- a/slog/benchmarks/benchmarks_test.go
+++ b/slog/benchmarks/benchmarks_test.go
@@ -145,3 +145,55 @@ func BenchmarkAttrs(b *testing.B) {
 		})
 	}
 }
+
+func BenchmarkWith(b *testing.B) {
+	for _, handler := range []struct {
+		name string
+		h    slog.Handler
+	}{
+		{"Text discard", slog.NewTextHandler(io.Discard)},
+		{"JSON discard", slog.NewJSONHandler(io.Discard)},
+	} {
+		logger := slog.New(handler.h)
+		b.Run(handler.name, func(b *testing.B) {
+			for _, call := range []struct {
+				name string
+				args []any
+			}{
+				{
+					"no parameters",
+					[]any{},
+				},
+				{
+					"1 key/value pair",
+					[]any{
+						"string", TestString,
+					},
+				},
+				{
+					"5 key/value pairs",
+					[]any{
+						"string", TestString,
+						"status", TestInt,
+						"duration", TestDuration,
+						"time", TestTime,
+						"error", TestError,
+					},
+				},
+			} {
+				b.Run(call.name, func(b *testing.B) {
+					b.ReportAllocs()
+					b.RunParallel(func(pb *testing.PB) {
+						l := logger
+						for pb.Next() {
+							l = logger.With(call.args...)
+						}
+						globalLogger = l
+					})
+				})
+			}
+		})
+	}
+}
+
+var globalLogger slog.Logger
diff --git a/slog/logger.go b/slog/logger.go
index 8f021e6f6..d7e38cac8 100644
--- a/slog/logger.go
+++ b/slog/logger.go
@@ -21,7 +21,7 @@ func init() {
 }
 
 // Default returns the default Logger.
-func Default() *Logger { return defaultLogger.Load().(*Logger) }
+func Default() Logger { return *defaultLogger.Load().(*Logger) }
 
 // SetDefault makes l the default Logger.
 // After this call, output from the log package's default Logger
@@ -94,7 +94,7 @@ func (l *Logger) Handler() Handler { return l.handler }
 // The new Logger shares the old Logger's context.
 // The new Logger's handler is the result of calling WithAttrs on the receiver's
 // handler.
-func (l *Logger) With(args ...any) *Logger {
+func (l Logger) With(args ...any) Logger {
 	var (
 		attr  Attr
 		attrs []Attr
@@ -103,7 +103,7 @@ func (l *Logger) With(args ...any) *Logger {
 		attr, args = argsToAttr(args)
 		attrs = append(attrs, attr)
 	}
-	c := l.clone()
+	c := l
 	c.handler = l.handler.WithAttrs(attrs)
 	return c
 }
@@ -122,15 +122,15 @@ func (l *Logger) WithGroup(name string) *Logger {
 }
 
 // New creates a new Logger with the given non-nil Handler and a nil context.
-func New(h Handler) *Logger {
+func New(h Handler) Logger {
 	if h == nil {
 		panic("nil Handler")
 	}
-	return &Logger{handler: h}
+	return Logger{handler: h}
 }
 
 // With calls Logger.With on the default logger.
-func With(args ...any) *Logger {
+func With(args ...any) Logger {
 	return Default().With(args...)
 }
 
@@ -211,7 +211,7 @@ func (l *Logger) ErrorCtx(ctx context.Context, msg string, args ...any) {
 // log is the low-level logging method for methods that take ...any.
 // It must always be called directly by an exported logging method
 // or function, because it uses a fixed call depth to obtain the pc.
-func (l *Logger) log(ctx context.Context, level Level, msg string, args ...any) {
+func (l Logger) log(ctx context.Context, level Level, msg string, args ...any) {
 	if !l.Enabled(ctx, level) {
 		return
 	}
@@ -231,7 +231,7 @@ func (l *Logger) log(ctx context.Context, level Level, msg string, args ...any)
 }
 
 // logAttrs is like [Logger.log], but for methods that take ...Attr.
-func (l *Logger) logAttrs(ctx context.Context, level Level, msg string, attrs ...Attr) {
+func (l Logger) logAttrs(ctx context.Context, level Level, msg string, attrs ...Attr) {
 	if !l.Enabled(ctx, level) {
 		return
 	}
diff --git a/slog/logger_test.go b/slog/logger_test.go
index 2f04540c8..b8323ada6 100644
--- a/slog/logger_test.go
+++ b/slog/logger_test.go
@@ -498,3 +498,11 @@ func callerPC(depth int) uintptr {
 	runtime.Callers(depth, pcs[:])
 	return pcs[0]
 }
+
+func TestNullLogger(t *testing.T) {
+	var logger Logger
+	enabled := logger.Enabled(context.Background(), LevelInfo)
+	if enabled {
+		t.Error("null Logger should disable logging")
+	}
+}