diff --git a/plugins/wporg-5ftf/includes/contributor.php b/plugins/wporg-5ftf/includes/contributor.php
index b8f5d42..20aeced 100644
--- a/plugins/wporg-5ftf/includes/contributor.php
+++ b/plugins/wporg-5ftf/includes/contributor.php
@@ -760,7 +760,7 @@ function prune_unnotifiable_users( array $contributors ) : array {
 	$inactivity_threshold = strtotime( INACTIVITY_THRESHOLD_MONTHS . ' months ago' );
 
 	foreach ( $contributors as $index => $contributor ) {
-		if ( $contributor['last_logged_in'] > $inactivity_threshold ) {
+		if ( is_active( $contributor['last_logged_in'] ) ) {
 			unset( $contributors[ $index ] );
 		}
 
@@ -772,6 +772,18 @@ function prune_unnotifiable_users( array $contributors ) : array {
 	return $contributors;
 }
 
+/**
+ * Determine if a contributor is active or not.
+ *
+ * Currently this only tracks the last login, but in the future it will be expanded to be more granular.
+ * @link https://github.com/WordPress/five-for-the-future/issues/210
+ */
+function is_active( int $last_login ) : bool {
+	$inactivity_threshold = strtotime( INACTIVITY_THRESHOLD_MONTHS . ' months ago' );
+
+	return $last_login > $inactivity_threshold;
+}
+
 /**
  * Notify an inactive contributor.
  */
diff --git a/plugins/wporg-5ftf/tests/test-contributor.php b/plugins/wporg-5ftf/tests/test-contributor.php
index 8e15574..24b37d7 100644
--- a/plugins/wporg-5ftf/tests/test-contributor.php
+++ b/plugins/wporg-5ftf/tests/test-contributor.php
@@ -5,10 +5,12 @@ use WordPressDotOrg\FiveForTheFuture\{ Contributor, Pledge, XProfile };
 defined( 'WPINC' ) || die();
 
 /**
- * These are integration tests rather than unit tests. They target the the highest functions in the call stack
+ * Some of these are integration tests rather than unit tests. They target the the highest functions in the call stack
  * in order to test everything beneath them, to the extent that that's practical. `INPUT_POST` can't be mocked,
  * so functions that reference it can't be used.
  *
+ * Mocking that can become unwieldy, though, so sometimes unit tests are more practical.
+ *
  * @group contributor
  */
 class Test_Contributor extends WP_UnitTestCase {
@@ -265,4 +267,37 @@ class Test_Contributor extends WP_UnitTestCase {
 		$this->assertContains( $jane->user_email, $mailer->mock_sent[0]['to'][0] );
 		$this->assertSame( "Removed from $tenup->post_title Five for the Future pledge", $mailer->mock_sent[0]['subject'] );
 	}
+
+	/**
+	 * @covers ::prune_unnotifiable_users
+	 */
+	public function test_prune_unnotifiable_users() {
+		$contributors = array(
+			'active + due for email' => array(
+				'last_logged_in'             => strtotime( '1 week ago' ),
+				'5ftf_last_inactivity_email' => 0,
+			),
+
+			'active + not due for email' => array(
+				'last_logged_in'             => strtotime( '1 week ago' ),
+				'5ftf_last_inactivity_email' => strtotime( '1 month ago' ),
+			),
+
+			'inactive + due for email' => array(
+				'last_logged_in'             => strtotime( '4 months ago' ),
+				'5ftf_last_inactivity_email' => strtotime( '4 months ago' ),
+			),
+
+			'inactive + not due for email' => array(
+				'last_logged_in'             => strtotime( '4 months ago' ),
+				'5ftf_last_inactivity_email' => strtotime( '2 months ago' ),
+			),
+		);
+
+		$expected = array( 'inactive + due for email' );
+
+		$actual = Contributor\prune_unnotifiable_users( $contributors );
+
+		$this->assertSame( $expected, array_keys( $actual ) );
+	}
 }