diff --git a/admin/admin.php b/admin/admin.php
index c2ee737..6671a9e 100644
--- a/admin/admin.php
+++ b/admin/admin.php
@@ -406,7 +406,7 @@ public function options_validate( array $input ): array {
 	 * @return bool
 	 */
 	private function sanitize_bool( $value ): bool {
-		return ( $value || ! empty( $value ) );
+		return (bool) $value;
 	}
 
 	/**
diff --git a/admin/comment-parent.php b/admin/comment-parent.php
index 04541de..c4ef619 100644
--- a/admin/comment-parent.php
+++ b/admin/comment-parent.php
@@ -38,18 +38,16 @@ public function comment_parent_box( $comment ) { // phpcs:ignore Generic.CodeAna
 	 * @return void
 	 */
 	public function load_comment_parent_box() {
-		if ( \function_exists( 'add_meta_box' ) ) {
-			\add_meta_box(
-				'comment_parent',
-				\esc_html__( 'Comment Parent', 'yoast-comment-hacks' ),
-				[
-					$this,
-					'comment_parent_box',
-				],
-				'comment',
-				'normal'
-			);
-		}
+		\add_meta_box(
+			'comment_parent',
+			\esc_html__( 'Comment Parent', 'yoast-comment-hacks' ),
+			[
+				$this,
+				'comment_parent_box',
+			],
+			'comment',
+			'normal'
+		);
 	}
 
 	/**
@@ -70,11 +68,10 @@ public function update_comment_parent() {
 			return; // There might be another reason for a comment to be updated.
 		}
 
-		if ( \function_exists( 'wp_doing_ajax' ) && \wp_doing_ajax() ) {
+		if ( \wp_doing_ajax() ) {
 			\check_ajax_referer( 'replyto-comment', '_ajax_nonce-replyto-comment' );
 		}
-
-		if ( ! \function_exists( 'wp_doing_ajax' ) || ! \wp_doing_ajax() ) {
+		else {
 			\check_admin_referer( 'update-comment_' . $comment_id );
 		}
 
diff --git a/inc/clean-emails.php b/inc/clean-emails.php
index 0b60b51..9c251d2 100644
--- a/inc/clean-emails.php
+++ b/inc/clean-emails.php
@@ -304,14 +304,12 @@ private function comment_notification_actions(): void {
 	 * @return void
 	 */
 	private function comment_action_links( array $actions ): void {
-		$links = '';
+		$links = [];
 		foreach ( $actions as $action => $label ) {
-			$links .= $this->comment_action_link( $label, $action ) . ' | ';
+			$links[] = $this->comment_action_link( $label, $action );
 		}
 
-		$links = \rtrim( $links, '| ' );
-
-		$this->message .= $links;
+		$this->message .= \implode( ' | ', $links );
 	}
 
 	/**
diff --git a/inc/hacks.php b/inc/hacks.php
index 631c51c..20df2c9 100644
--- a/inc/hacks.php
+++ b/inc/hacks.php
@@ -165,7 +165,7 @@ public function modify_comment_edit_link_block( $block_content, $block ) {
 	public function get_remove_comment_url_link( $comment_id ) {
 		$comment = \get_comment( $comment_id );
 
-		if ( isset( $comment ) && $comment instanceof WP_Comment && ! empty( $comment->comment_author_url ) ) {
+		if ( $comment instanceof WP_Comment && ! empty( $comment->comment_author_url ) ) {
 			return \sprintf(
 				'<a href="#" class="comment-remove-url" data-comment-id="%d" aria-label="%s">%s</a>',
 				\esc_attr( (string) $comment_id ),
diff --git a/inc/notifications.php b/inc/notifications.php
index 77ac734..5f79703 100644
--- a/inc/notifications.php
+++ b/inc/notifications.php
@@ -55,18 +55,13 @@ public function filter_notification_recipients( $recipients, $comment_id ): arra
 	public function filter_notification_headers( $message_headers, $comment_id ): string {
 		$comment = \get_comment( $comment_id );
 
-		if ( $comment->comment_author !== '' && $comment->comment_author_email !== '' ) {
-			$name             = \esc_html( $comment->comment_author );
-			$message_headers .= "\nReply-To: $name <$comment->comment_author_email>\n";
-
+		if ( $comment->comment_author_email === '' ) {
 			return $message_headers;
 		}
 
-		if ( $comment->comment_author_email !== '' ) {
-			$message_headers .= "\nReply-To: $comment->comment_author_email <$comment->comment_author_email>\n";
+		$name = ( $comment->comment_author !== '' ) ? \esc_html( $comment->comment_author ) : $comment->comment_author_email;
 
-			return $message_headers;
-		}
+		$message_headers .= "\nReply-To: $name <$comment->comment_author_email>\n";
 
 		return $message_headers;
 	}
diff --git a/inc/progress-planner/comment-policy.php b/inc/progress-planner/comment-policy.php
index 1f78838..54d0491 100644
--- a/inc/progress-planner/comment-policy.php
+++ b/inc/progress-planner/comment-policy.php
@@ -83,11 +83,7 @@ public function get_description() {
 	 * @return bool
 	 */
 	public function should_add_task() {
-		if ( ! (int) $this->options['comment_policy_page'] || ! (int) $this->options['comment_policy'] ) {
-			return true;
-		}
-
-		return false;
+		return ! (int) $this->options['comment_policy_page'] || ! (int) $this->options['comment_policy'];
 	}
 
 	/**
diff --git a/inc/progress-planner/comment-redirect.php b/inc/progress-planner/comment-redirect.php
index 0cfb46c..2f4741f 100644
--- a/inc/progress-planner/comment-redirect.php
+++ b/inc/progress-planner/comment-redirect.php
@@ -82,11 +82,7 @@ public function get_description() {
 	 * @return bool
 	 */
 	public function should_add_task() {
-		if ( ! $this->options['redirect_page'] ) {
-			return true;
-		}
-
-		return false;
+		return ! $this->options['redirect_page'];
 	}
 
 	/**