diff --git a/Signal/src/ViewControllers/ConversationView/ConversationViewController.m b/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
index 037d2383a..91a0d8720 100644
--- a/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
+++ b/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "ConversationViewController.h"
@@ -497,7 +497,7 @@ typedef enum : NSUInteger {
     }
 
     TSGroupThread *groupThread = (TSGroupThread *)self.thread;
-    return ![groupThread.groupModel.groupMemberIds containsObject:self.tsAccountManager.localNumber];
+    return !groupThread.isLocalUserInGroup;
 }
 
 - (void)hideInputIfNeeded
@@ -1258,8 +1258,7 @@ typedef enum : NSUInteger {
     } else {
         OWSAssertDebug(self.thread.contactIdentifier);
 
-        BOOL isNoteToSelf = [self.thread.contactIdentifier isEqualToString:self.tsAccountManager.localNumber];
-        if (isNoteToSelf) {
+        if (self.thread.isNoteToSelf) {
             name = [[NSAttributedString alloc]
                 initWithString:NSLocalizedString(@"NOTE_TO_SELF", @"Label for 1:1 conversation with yourself.")
                     attributes:@{
diff --git a/Signal/src/ViewControllers/HomeView/HomeViewCell.m b/Signal/src/ViewControllers/HomeView/HomeViewCell.m
index 5a86f96c6..820598db2 100644
--- a/Signal/src/ViewControllers/HomeView/HomeViewCell.m
+++ b/Signal/src/ViewControllers/HomeView/HomeViewCell.m
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "HomeViewCell.h"
@@ -517,8 +517,7 @@ NS_ASSUME_NONNULL_BEGIN
             name = [[NSAttributedString alloc] initWithString:thread.name];
         }
     } else {
-        BOOL isNoteToSelf = [self.thread.contactIdentifier isEqualToString:self.tsAccountManager.localNumber];
-        if (isNoteToSelf) {
+        if (self.thread.threadRecord.isNoteToSelf) {
             name = [[NSAttributedString alloc]
                 initWithString:NSLocalizedString(@"NOTE_TO_SELF", @"Label for 1:1 conversation with yourself.")
                     attributes:@{
diff --git a/Signal/src/ViewControllers/ThreadSettings/OWSConversationSettingsViewController.m b/Signal/src/ViewControllers/ThreadSettings/OWSConversationSettingsViewController.m
index 8a89940ca..4df03214e 100644
--- a/Signal/src/ViewControllers/ThreadSettings/OWSConversationSettingsViewController.m
+++ b/Signal/src/ViewControllers/ThreadSettings/OWSConversationSettingsViewController.m
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "OWSConversationSettingsViewController.h"
@@ -310,8 +310,7 @@ const CGFloat kIconViewLength = 24;
     OWSTableContents *contents = [OWSTableContents new];
     contents.title = NSLocalizedString(@"CONVERSATION_SETTINGS", @"title for conversation settings screen");
 
-    BOOL isNoteToSelf = (!self.thread.isGroupThread &&
-        [self.thread.contactIdentifier isEqualToString:self.tsAccountManager.localNumber]);
+    BOOL isNoteToSelf = self.thread.isNoteToSelf;
 
     __weak OWSConversationSettingsViewController *weakSelf = self;
 
@@ -1085,8 +1084,7 @@ const CGFloat kIconViewLength = 24;
 {
     if (self.isGroupThread) {
         TSGroupThread *groupThread = (TSGroupThread *)self.thread;
-        BOOL inGroup = [groupThread.groupModel.groupMemberIds containsObject:TSAccountManager.localNumber];
-        return !inGroup;
+        return !groupThread.isLocalUserInGroup;
     }
 
     return NO;
diff --git a/SignalServiceKit/src/Account/TSAccountManager.h b/SignalServiceKit/src/Account/TSAccountManager.h
index bf6f6cd95..dece93ae6 100644
--- a/SignalServiceKit/src/Account/TSAccountManager.h
+++ b/SignalServiceKit/src/Account/TSAccountManager.h
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "TSConstants.h"
@@ -59,7 +59,7 @@ typedef NS_ENUM(NSUInteger, OWSRegistrationState) {
 - (nullable NSString *)localNumber;
 
 // A variant of localNumber that never opens a "sneaky" transaction.
-- (nullable NSString *)storedLocalNumber:(YapDatabaseReadTransaction *)transaction;
+- (nullable NSString *)storedOrCachedLocalNumber:(YapDatabaseReadTransaction *)transaction;
 
 /**
  *  Symmetric key that's used to encrypt message payloads from the server,
diff --git a/SignalServiceKit/src/Account/TSAccountManager.m b/SignalServiceKit/src/Account/TSAccountManager.m
index ea80c5f1a..21798c5b3 100644
--- a/SignalServiceKit/src/Account/TSAccountManager.m
+++ b/SignalServiceKit/src/Account/TSAccountManager.m
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "TSAccountManager.h"
@@ -220,8 +220,14 @@ NSString *const TSAccountManager_NeedsAccountAttributesUpdateKey = @"TSAccountMa
     }
 }
 
-- (nullable NSString *)storedLocalNumber:(YapDatabaseReadTransaction *)transaction
+- (nullable NSString *)storedOrCachedLocalNumber:(YapDatabaseReadTransaction *)transaction
 {
+    @synchronized(self) {
+        if (self.cachedLocalNumber) {
+            return self.cachedLocalNumber;
+        }
+    }
+
     return [transaction stringForKey:TSAccountManager_RegisteredNumberKey
                         inCollection:TSAccountManager_UserAccountCollection];
 }
diff --git a/SignalServiceKit/src/Contacts/TSThread.h b/SignalServiceKit/src/Contacts/TSThread.h
index 0b2b3dd32..2aa098655 100644
--- a/SignalServiceKit/src/Contacts/TSThread.h
+++ b/SignalServiceKit/src/Contacts/TSThread.h
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "TSYapDatabaseObject.h"
@@ -68,6 +68,8 @@ extern ConversationColorName const kConversationColorName_Default;
  */
 @property (nonatomic, readonly) NSArray<NSString *> *recipientIdentifiers;
 
+- (BOOL)isNoteToSelf;
+
 #pragma mark Interactions
 
 /**
diff --git a/SignalServiceKit/src/Contacts/TSThread.m b/SignalServiceKit/src/Contacts/TSThread.m
index 7ab1e04fa..26eb0b697 100644
--- a/SignalServiceKit/src/Contacts/TSThread.m
+++ b/SignalServiceKit/src/Contacts/TSThread.m
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "TSThread.h"
@@ -7,6 +7,8 @@
 #import "OWSDisappearingMessagesConfiguration.h"
 #import "OWSPrimaryStorage.h"
 #import "OWSReadTracking.h"
+#import "SSKEnvironment.h"
+#import "TSAccountManager.h"
 #import "TSDatabaseView.h"
 #import "TSIncomingMessage.h"
 #import "TSInfoMessage.h"
@@ -55,6 +57,17 @@ ConversationColorName const kConversationColorName_Default = ConversationColorNa
 
 @implementation TSThread
 
+#pragma mark - Dependencies
+
+- (TSAccountManager *)tsAccountManager
+{
+    OWSAssertDebug(SSKEnvironment.shared.tsAccountManager);
+
+    return SSKEnvironment.shared.tsAccountManager;
+}
+
+#pragma mark -
+
 + (NSString *)collection {
     return @"TSThread";
 }
@@ -179,7 +192,13 @@ ConversationColorName const kConversationColorName_Default = ConversationColorNa
     }
 }
 
-#pragma mark To be subclassed.
+- (BOOL)isNoteToSelf
+{
+    return (!self.isGroupThread && self.contactIdentifier != nil &&
+        [self.contactIdentifier isEqualToString:self.tsAccountManager.localNumber]);
+}
+
+#pragma mark - To be subclassed.
 
 - (BOOL)isGroupThread {
     OWSAbstractMethod();
@@ -211,7 +230,7 @@ ConversationColorName const kConversationColorName_Default = ConversationColorNa
     return NO;
 }
 
-#pragma mark Interactions
+#pragma mark - Interactions
 
 /**
  * Iterate over this thread's interactions
@@ -405,7 +424,7 @@ ConversationColorName const kConversationColorName_Default = ConversationColorNa
     }
 }
 
-#pragma mark Disappearing Messages
+#pragma mark - Disappearing Messages
 
 - (OWSDisappearingMessagesConfiguration *)disappearingMessagesConfigurationWithTransaction:
     (YapDatabaseReadTransaction *)transaction
diff --git a/SignalServiceKit/src/Messages/OWSMessageManager.m b/SignalServiceKit/src/Messages/OWSMessageManager.m
index 9e776942a..ecc24734e 100644
--- a/SignalServiceKit/src/Messages/OWSMessageManager.m
+++ b/SignalServiceKit/src/Messages/OWSMessageManager.m
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "OWSMessageManager.h"
@@ -511,7 +511,7 @@ NS_ASSUME_NONNULL_BEGIN
 
         if (groupThread) {
             if (dataMessage.group.type != SSKProtoGroupContextTypeUpdate) {
-                if (![groupThread.groupModel.groupMemberIds containsObject:self.tsAccountManager.localNumber]) {
+                if (!groupThread.isLocalUserInGroup) {
                     OWSLogInfo(@"Ignoring messages for left group.");
                     return;
                 }
@@ -705,7 +705,7 @@ NS_ASSUME_NONNULL_BEGIN
     if (typingMessage.hasGroupID) {
         TSGroupThread *groupThread = [TSGroupThread threadWithGroupId:typingMessage.groupID transaction:transaction];
 
-        if (![groupThread.groupModel.groupMemberIds containsObject:self.tsAccountManager.localNumber]) {
+        if (!groupThread.isLocalUserInGroup) {
             OWSLogInfo(@"Ignoring messages for left group.");
             return;
         }
@@ -1135,8 +1135,7 @@ NS_ASSUME_NONNULL_BEGIN
     }
 
     // Ensure we are in the group.
-    NSString *localNumber = self.tsAccountManager.localNumber;
-    if (![gThread.groupModel.groupMemberIds containsObject:localNumber]) {
+    if (!gThread.isLocalUserInGroup) {
         OWSLogWarn(@"Ignoring 'Request Group Info' message for group we no longer belong to.");
         return;
     }
diff --git a/SignalServiceKit/src/Storage/FullTextSearchFinder.swift b/SignalServiceKit/src/Storage/FullTextSearchFinder.swift
index 899a3e96d..234c45287 100644
--- a/SignalServiceKit/src/Storage/FullTextSearchFinder.swift
+++ b/SignalServiceKit/src/Storage/FullTextSearchFinder.swift
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -192,7 +192,7 @@ public class FullTextSearchFinder: NSObject {
 
         var result = "\(recipientId) \(nationalNumber) \(displayName)"
 
-        if let localNumber = tsAccountManager.storedLocalNumber(transaction) {
+        if let localNumber = tsAccountManager.storedOrCachedLocalNumber(transaction) {
             if localNumber == recipientId {
                 let noteToSelfLabel = NSLocalizedString("NOTE_TO_SELF", comment: "Label for 1:1 conversation with yourself.")
                 result += " \(noteToSelfLabel)"