diff --git a/docs/laravel-feeds.tree b/docs/laravel-feeds.tree
index 20fb58b..4c8afcb 100644
--- a/docs/laravel-feeds.tree
+++ b/docs/laravel-feeds.tree
@@ -26,6 +26,7 @@
         <toc-element topic="location.topic" />
         <toc-element topic="presets.topic" />
         <toc-element topic="events.topic" />
+        <toc-element topic="extending-functionality.topic" />
     </toc-element>
     <toc-element toc-title="Receipts">
         <toc-element topic="receipt-sitemap.topic" />
diff --git a/docs/snippets/advanced-extends-conditional-both.php b/docs/snippets/advanced-extends-conditional-both.php
new file mode 100644
index 0000000..ba9c1e6
--- /dev/null
+++ b/docs/snippets/advanced-extends-conditional-both.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+use DragonCode\LaravelFeed\Feeds\Feed;
+use DragonCode\LaravelFeed\Feeds\Items\FeedItem;
+use Illuminate\Database\Eloquent\Model;
+
+class ProductFeed extends Feed
+{
+    public function item(Model $model): FeedItem
+    {
+        return (new ProductFeedItem($model))
+            ->when(
+                value   : $model->category,
+                callback: function (ProductFeedItem $item) {
+                    $item->title .= ' (first)';
+                },
+                default : function (ProductFeedItem $item) {
+                    $item->title .= ' (second)';
+                },
+            );
+    }
+}
diff --git a/docs/snippets/advanced-extends-conditional-unless.php b/docs/snippets/advanced-extends-conditional-unless.php
new file mode 100644
index 0000000..74dcaa3
--- /dev/null
+++ b/docs/snippets/advanced-extends-conditional-unless.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+use DragonCode\LaravelFeed\Feeds\Feed;
+use DragonCode\LaravelFeed\Feeds\Items\FeedItem;
+use Illuminate\Database\Eloquent\Model;
+
+class ProductFeed extends Feed
+{
+    public function item(Model $model): FeedItem
+    {
+        return (new ProductFeedItem($model))
+            ->unless(
+                value   : $model->category,
+                callback: function (ProductFeedItem $item) {
+                    $item->title .= ' (second)';
+                },
+                default : function (ProductFeedItem $item) {
+                    $item->title .= ' (first)';
+                },
+            );
+    }
+}
diff --git a/docs/snippets/advanced-extends-conditional.php b/docs/snippets/advanced-extends-conditional.php
new file mode 100644
index 0000000..5fb4f87
--- /dev/null
+++ b/docs/snippets/advanced-extends-conditional.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+use DragonCode\LaravelFeed\Feeds\Feed;
+use DragonCode\LaravelFeed\Feeds\Items\FeedItem;
+use Illuminate\Database\Eloquent\Model;
+
+class ProductFeed extends Feed
+{
+    public function item(Model $model): FeedItem
+    {
+        return (new ProductFeedItem($model))
+            ->when($model->category, function (ProductFeedItem $item) {
+                $item->title .= ' (first)';
+            });
+    }
+}
diff --git a/docs/snippets/advanced-extends-macro-feed.php b/docs/snippets/advanced-extends-macro-feed.php
new file mode 100644
index 0000000..d63eb17
--- /dev/null
+++ b/docs/snippets/advanced-extends-macro-feed.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+use DragonCode\LaravelFeed\Feeds\Feed;
+use Illuminate\Support\ServiceProvider;
+
+class FeedServiceProvider extends ServiceProvider
+{
+    public function boot(): void
+    {
+        Feed::macro('customFilename', function (Feed $feed, string $name) {
+            $this->filename = $name;
+
+            return $this;
+        });
+    }
+}
diff --git a/docs/snippets/advanced-extends-macro-info.php b/docs/snippets/advanced-extends-macro-info.php
new file mode 100644
index 0000000..c636d12
--- /dev/null
+++ b/docs/snippets/advanced-extends-macro-info.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+use DragonCode\LaravelFeed\Feeds\Info\FeedInfo;
+use Illuminate\Support\ServiceProvider;
+
+class FeedServiceProvider extends ServiceProvider
+{
+    public function boot(): void
+    {
+        FeedInfo::macro('titleWithPrefix', function () {
+            return sprintf('[%s]: %s', date('Y'), $this->title);
+        });
+    }
+}
+
+class ProductFeedInfo extends FeedInfo
+{
+    public function __construct(
+        protected string $title,
+    ) {}
+
+    public function toArray(): array
+    {
+        return [
+            'title' => $this->titleWithPrefix(),
+        ];
+    }
+}
diff --git a/docs/snippets/advanced-extends-macro-item.php b/docs/snippets/advanced-extends-macro-item.php
new file mode 100644
index 0000000..e6a1cd3
--- /dev/null
+++ b/docs/snippets/advanced-extends-macro-item.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+use DragonCode\LaravelFeed\Feeds\Items\FeedItem;
+use Illuminate\Support\ServiceProvider;
+
+class FeedServiceProvider extends ServiceProvider
+{
+    public function boot(): void
+    {
+        FeedItem::macro('titleWithPrefix', function () {
+            return sprintf('[%s]: %s]', $this->model->getKey(), $this->model->title);
+        });
+    }
+}
+
+class ProductFeedItem extends FeedItem
+{
+    public function toArray(): array
+    {
+        return [
+            'title' => $this->titleWithPrefix(),
+        ];
+    }
+}
diff --git a/docs/topics/extending-functionality.topic b/docs/topics/extending-functionality.topic
new file mode 100644
index 0000000..6dc0413
--- /dev/null
+++ b/docs/topics/extending-functionality.topic
@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE topic
+        SYSTEM "https://resources.jetbrains.com/writerside/1.0/xhtml-entities.dtd">
+<topic
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:noNamespaceSchemaLocation="https://resources.jetbrains.com/writerside/1.0/topic.v2.xsd"
+        title="Extending functionality" id="extending-functionality">
+
+    <link-summary>Extend feeds using conditional clauses and macros for Feed, FeedItem, and FeedInfo.</link-summary>
+    <card-summary>Extend feeds using conditional clauses and macros for Feed, FeedItem, and FeedInfo.</card-summary>
+    <web-summary>Extend feeds using conditional clauses and macros for Feed, FeedItem, and FeedInfo.</web-summary>
+
+    <show-structure depth="3" />
+
+    <chapter title="Conditional clauses" id="conditional_clauses">
+        <note>
+            Conditional clauses are available for <code>Feed</code>, <code>FeedInfo</code> and
+            <code>FeedItem</code> classes.
+        </note>
+
+        <p>
+            Sometimes, you may want certain feed clauses to apply to a feed based on another condition.
+            For instance, you may only want to apply a where statement if a given input value is present or another attribute has a value.
+            You can accomplish this using the <code>when</code> method:
+        </p>
+
+        <code-block lang="php" src="advanced-extends-conditional.php" include-lines="5-" />
+
+        <p>
+            The <code>when</code> method only executes the given closure when the first argument is <code>true</code>.
+            If the first argument is <code>false</code>, the closure will not be executed.
+            So, in the example above, the closure given to the <code>when</code> method will only be invoked if the
+            <code>category</code> field is present on the model and evaluates to <code>true</code>.
+        </p>
+
+        <p>
+            You may pass another closure as the third argument to the <code>when</code> method.
+            This closure will only execute if the first argument evaluates to <code>false</code>.
+            To illustrate how this feature may be used, we will use it to configure the model title suffix:
+        </p>
+
+        <code-block lang="php" src="advanced-extends-conditional-both.php" include-lines="5-" />
+
+        <p>
+            Additionally, the inverse method <code>unless</code> is available.
+            In this case, the processing logic is the exact opposite.
+        </p>
+
+        <code-block lang="php" src="advanced-extends-conditional-unless.php" include-lines="5-" />
+    </chapter>
+
+    <chapter title="Macroable" id="macroable">
+        <p>
+            <code>Feed</code>, <code>FeedItem</code>, and <code>FeedInfo</code> are "macroable",
+            which allows you to add additional methods to them at runtime.
+            The <code>macro</code> method accepts a closure that will be executed when your macro is called.
+            The macro closure may access the feed's other methods via <code>$this</code>,
+            just as if it were a real method of the feed classes.
+        </p>
+
+        <p>
+            For example, the following code adds a <code>customFilename</code> method to the <code>Feed</code> class:
+        </p>
+
+        <code-block lang="php" src="advanced-extends-macro-feed.php" include-lines="5-" />
+
+        <p>
+            Additionally, here are examples for <code>FeedInfo</code> and <code>FeedItem</code>:
+        </p>
+
+        <code-block lang="php" src="advanced-extends-macro-info.php" include-lines="5-" />
+        <code-block lang="php" src="advanced-extends-macro-item.php" include-lines="5-" />
+    </chapter>
+</topic>
diff --git a/src/Feeds/Feed.php b/src/Feeds/Feed.php
index 2b1dfac..7a0e465 100644
--- a/src/Feeds/Feed.php
+++ b/src/Feeds/Feed.php
@@ -14,11 +14,16 @@
 use Illuminate\Foundation\Application;
 use Illuminate\Support\Facades\Storage;
 use Illuminate\Support\Str;
+use Illuminate\Support\Traits\Conditionable;
+use Illuminate\Support\Traits\Macroable;
 
 use function class_basename;
 
 abstract class Feed
 {
+    use Conditionable;
+    use Macroable;
+
     protected FeedFormatEnum $format = FeedFormatEnum::Xml;
 
     protected string $storage = 'public';
diff --git a/src/Feeds/Info/FeedInfo.php b/src/Feeds/Info/FeedInfo.php
index 14aa3fe..708f1a1 100644
--- a/src/Feeds/Info/FeedInfo.php
+++ b/src/Feeds/Info/FeedInfo.php
@@ -5,9 +5,14 @@
 namespace DragonCode\LaravelFeed\Feeds\Info;
 
 use Illuminate\Contracts\Support\Arrayable;
+use Illuminate\Support\Traits\Conditionable;
+use Illuminate\Support\Traits\Macroable;
 
 class FeedInfo implements Arrayable
 {
+    use Conditionable;
+    use Macroable;
+
     public function toArray(): array
     {
         return [];
diff --git a/src/Feeds/Items/FeedItem.php b/src/Feeds/Items/FeedItem.php
index d7d5900..cab2d45 100644
--- a/src/Feeds/Items/FeedItem.php
+++ b/src/Feeds/Items/FeedItem.php
@@ -7,11 +7,16 @@
 use Illuminate\Contracts\Support\Arrayable;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Support\Str;
+use Illuminate\Support\Traits\Conditionable;
+use Illuminate\Support\Traits\Macroable;
 
 use function class_basename;
 
 class FeedItem implements Arrayable
 {
+    use Conditionable;
+    use Macroable;
+
     protected ?string $name = null;
 
     public function __construct(