diff --git a/src/retention.rs b/src/retention.rs
index f381d6e..4a4f57f 100644
--- a/src/retention.rs
+++ b/src/retention.rs
@@ -3,23 +3,23 @@ mod message_age;
 pub use message_age::MessageAge;
 
 /// Retention policy configuration for email messages.
-/// 
+///
 /// A retention policy defines how old messages should be before they are subject
 /// to retention actions (trash/delete), and whether a label should be automatically
 /// generated to categorize messages matching this policy.
-/// 
+///
 /// # Examples
-/// 
+///
 /// ```
 /// use cull_gmail::{Retention, MessageAge};
-/// 
+///
 /// // Create a retention policy for messages older than 6 months
 /// let policy = Retention::new(MessageAge::Months(6), true);
-/// 
+///
 /// // Create a retention policy without auto-generated labels
 /// let policy = Retention::new(MessageAge::Years(1), false);
 /// ```
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Retention {
     age: MessageAge,
     generate_label: bool,
@@ -36,20 +36,20 @@ impl Default for Retention {
 
 impl Retention {
     /// Create a new retention policy.
-    /// 
+    ///
     /// # Arguments
-    /// 
+    ///
     /// * `age` - The message age threshold for this retention policy
     /// * `generate_label` - Whether to automatically generate a label for messages matching this policy
-    /// 
+    ///
     /// # Examples
-    /// 
+    ///
     /// ```
     /// use cull_gmail::{Retention, MessageAge};
-    /// 
+    ///
     /// // Policy for messages older than 30 days with auto-generated label
     /// let policy = Retention::new(MessageAge::Days(30), true);
-    /// 
+    ///
     /// // Policy for messages older than 1 year without label generation
     /// let policy = Retention::new(MessageAge::Years(1), false);
     /// ```
@@ -61,46 +61,48 @@ impl Retention {
     }
 
     /// Get the message age threshold for this retention policy.
-    /// 
+    ///
     /// # Examples
-    /// 
+    ///
     /// ```
     /// use cull_gmail::{Retention, MessageAge};
-    /// 
+    ///
     /// let policy = Retention::new(MessageAge::Days(30), true);
     /// assert_eq!(policy.age(), &MessageAge::Days(30));
     /// ```
+    #[must_use]
     pub fn age(&self) -> &MessageAge {
         &self.age
     }
 
     /// Check if this retention policy should generate automatic labels.
-    /// 
+    ///
     /// When `true`, messages matching this retention policy will be automatically
     /// tagged with a generated label based on the age specification.
-    /// 
+    ///
     /// # Examples
-    /// 
+    ///
     /// ```
     /// use cull_gmail::{Retention, MessageAge};
-    /// 
+    ///
     /// let policy = Retention::new(MessageAge::Days(30), true);
     /// assert_eq!(policy.generate_label(), true);
-    /// 
+    ///
     /// let policy = Retention::new(MessageAge::Days(30), false);
     /// assert_eq!(policy.generate_label(), false);
     /// ```
+    #[must_use]
     pub fn generate_label(&self) -> bool {
         self.generate_label
     }
-    
+
     /// Set whether this retention policy should generate automatic labels.
-    /// 
+    ///
     /// # Examples
-    /// 
+    ///
     /// ```
     /// use cull_gmail::{Retention, MessageAge};
-    /// 
+    ///
     /// let mut policy = Retention::new(MessageAge::Days(30), false);
     /// policy.set_generate_label(true);
     /// assert_eq!(policy.generate_label(), true);
@@ -118,32 +120,32 @@ mod tests {
     fn test_retention_new() {
         let age = MessageAge::Days(30);
         let retention = Retention::new(age.clone(), true);
-        
+
         assert_eq!(retention.age(), &age);
-        assert_eq!(retention.generate_label(), true);
+        assert!(retention.generate_label());
     }
 
     #[test]
     fn test_retention_new_no_label() {
         let age = MessageAge::Years(1);
         let retention = Retention::new(age.clone(), false);
-        
+
         assert_eq!(retention.age(), &age);
-        assert_eq!(retention.generate_label(), false);
+        assert!(!retention.generate_label());
     }
 
     #[test]
     fn test_retention_set_generate_label() {
         let age = MessageAge::Months(6);
         let mut retention = Retention::new(age.clone(), false);
-        
-        assert_eq!(retention.generate_label(), false);
-        
+
+        assert!(!retention.generate_label());
+
         retention.set_generate_label(true);
-        assert_eq!(retention.generate_label(), true);
-        
+        assert!(retention.generate_label());
+
         retention.set_generate_label(false);
-        assert_eq!(retention.generate_label(), false);
+        assert!(!retention.generate_label());
     }
 
     #[test]
@@ -151,7 +153,7 @@ mod tests {
         let age = MessageAge::Weeks(2);
         let original = Retention::new(age.clone(), true);
         let cloned = original.clone();
-        
+
         assert_eq!(original, cloned);
         assert_eq!(original.age(), cloned.age());
         assert_eq!(original.generate_label(), cloned.generate_label());
@@ -162,23 +164,23 @@ mod tests {
         let age1 = MessageAge::Days(30);
         let age2 = MessageAge::Days(30);
         let age3 = MessageAge::Days(31);
-        
+
         let retention1 = Retention::new(age1, true);
         let retention2 = Retention::new(age2, true);
         let retention3 = Retention::new(age3, true);
         let retention4 = Retention::new(MessageAge::Days(30), false);
-        
+
         assert_eq!(retention1, retention2);
-        assert_ne!(retention1, retention3);  // different age
-        assert_ne!(retention1, retention4);  // different generate_label
+        assert_ne!(retention1, retention3); // different age
+        assert_ne!(retention1, retention4); // different generate_label
     }
 
     #[test]
     fn test_retention_default() {
         let default = Retention::default();
-        
+
         assert_eq!(default.age(), &MessageAge::Years(5));
-        assert_eq!(default.generate_label(), true);
+        assert!(default.generate_label());
     }
 
     #[test]
@@ -187,23 +189,23 @@ mod tests {
         let retention_weeks = Retention::new(MessageAge::Weeks(12), false);
         let retention_months = Retention::new(MessageAge::Months(3), true);
         let retention_years = Retention::new(MessageAge::Years(1), false);
-        
+
         assert_eq!(retention_days.age().period_type(), "days");
         assert_eq!(retention_weeks.age().period_type(), "weeks");
         assert_eq!(retention_months.age().period_type(), "months");
         assert_eq!(retention_years.age().period_type(), "years");
-        
-        assert_eq!(retention_days.generate_label(), true);
-        assert_eq!(retention_weeks.generate_label(), false);
-        assert_eq!(retention_months.generate_label(), true);
-        assert_eq!(retention_years.generate_label(), false);
+
+        assert!(retention_days.generate_label());
+        assert!(!retention_weeks.generate_label());
+        assert!(retention_months.generate_label());
+        assert!(!retention_years.generate_label());
     }
 
     #[test]
     fn test_retention_debug() {
         let retention = Retention::new(MessageAge::Days(30), true);
         let debug_str = format!("{:?}", retention);
-        
+
         assert!(debug_str.contains("Retention"));
         assert!(debug_str.contains("Days(30)"));
         assert!(debug_str.contains("true"));