diff --git a/gpt4all-backend/gptj.cpp b/gpt4all-backend/gptj.cpp
index 83855ed7..f0ce58a2 100644
--- a/gpt4all-backend/gptj.cpp
+++ b/gpt4all-backend/gptj.cpp
@@ -1013,7 +1013,7 @@ void GPTJ::prompt(const std::string &prompt,
             return;
 
         // Check if it partially matches our reverse prompts and if so, cache
-        for (auto s : reversePrompts) {
+        for (const auto &s : reversePrompts) {
             if (s.compare(0, completed.size(), completed) == 0) {
                 foundPartialReversePrompt = true;
                 cachedResponse = completed;
diff --git a/gpt4all-backend/llamamodel.cpp b/gpt4all-backend/llamamodel.cpp
index 86a7cc63..fd2e8fc9 100644
--- a/gpt4all-backend/llamamodel.cpp
+++ b/gpt4all-backend/llamamodel.cpp
@@ -278,7 +278,7 @@ void LLamaModel::prompt(const std::string &prompt,
         }
 
         // Check if it partially matches our reverse prompts and if so, cache
-        for (auto s : reversePrompts) {
+        for (const auto &s : reversePrompts) {
             if (s.compare(0, completed.size(), completed) == 0) {
                 foundPartialReversePrompt = true;
                 cachedResponse = completed;
diff --git a/gpt4all-backend/mpt.cpp b/gpt4all-backend/mpt.cpp
index b37dc2b6..4145c9c2 100644
--- a/gpt4all-backend/mpt.cpp
+++ b/gpt4all-backend/mpt.cpp
@@ -942,7 +942,7 @@ void MPT::prompt(const std::string &prompt,
             return;
 
         // Check if it partially matches our reverse prompts and if so, cache
-        for (auto s : reversePrompts) {
+        for (const auto &s : reversePrompts) {
             if (s.compare(0, completed.size(), completed) == 0) {
                 foundPartialReversePrompt = true;
                 cachedResponse = completed;
diff --git a/gpt4all-chat/chat.cpp b/gpt4all-chat/chat.cpp
index 3ae25616..a57f4997 100644
--- a/gpt4all-chat/chat.cpp
+++ b/gpt4all-chat/chat.cpp
@@ -387,7 +387,7 @@ QList<QString> Chat::modelList() const
         QDir dir(exePath);
         dir.setNameFilters(QStringList() << "ggml-*.bin");
         QStringList fileNames = dir.entryList();
-        for (QString f : fileNames) {
+        for (const QString& f : fileNames) {
             QString filePath = exePath + f;
             QFileInfo info(filePath);
             QString name = info.completeBaseName().remove(0, 5);
@@ -404,7 +404,7 @@ QList<QString> Chat::modelList() const
         QDir dir(localPath);
         dir.setNameFilters(QStringList() << "ggml-*.bin" << "chatgpt-*.txt");
         QStringList fileNames = dir.entryList();
-        for (QString f : fileNames) {
+        for (const QString &f : fileNames) {
             QString filePath = localPath + f;
             QFileInfo info(filePath);
             QString basename = info.completeBaseName();
diff --git a/gpt4all-chat/chatlistmodel.cpp b/gpt4all-chat/chatlistmodel.cpp
index 97cd018c..a794284d 100644
--- a/gpt4all-chat/chatlistmodel.cpp
+++ b/gpt4all-chat/chatlistmodel.cpp
@@ -118,7 +118,7 @@ void ChatsRestoreThread::run()
         QDir dir(settingsPath);
         dir.setNameFilters(QStringList() << "gpt4all-*.chat");
         QStringList fileNames = dir.entryList();
-        for (QString f : fileNames) {
+        for (const QString &f : fileNames) {
             QString filePath = settingsPath + "/" + f;
             QFile file(filePath);
             bool success = file.open(QIODevice::ReadOnly);
@@ -140,7 +140,7 @@ void ChatsRestoreThread::run()
         QDir dir(savePath);
         dir.setNameFilters(QStringList() << "gpt4all-*.chat");
         QStringList fileNames = dir.entryList();
-        for (QString f : fileNames) {
+        for (const QString &f : fileNames) {
             QString filePath = savePath + "/" + f;
             QFile file(filePath);
             bool success = file.open(QIODevice::ReadOnly);
diff --git a/gpt4all-chat/chatllm.cpp b/gpt4all-chat/chatllm.cpp
index 4804d492..7666fddc 100644
--- a/gpt4all-chat/chatllm.cpp
+++ b/gpt4all-chat/chatllm.cpp
@@ -546,7 +546,6 @@ bool ChatLLM::handleNameResponse(int32_t token, const std::string &response)
     emit generatedNameChanged();
     QString gen = QString::fromStdString(m_nameResponse).simplified();
     QStringList words = gen.split(' ', Qt::SkipEmptyParts);
-    int wordCount = words.size();
     return words.size() <= 3;
 }
 
diff --git a/gpt4all-chat/chatmodel.h b/gpt4all-chat/chatmodel.h
index 195a4887..2ff4f388 100644
--- a/gpt4all-chat/chatmodel.h
+++ b/gpt4all-chat/chatmodel.h
@@ -240,7 +240,7 @@ public:
     bool serialize(QDataStream &stream, int version) const
     {
         stream << count();
-        for (auto c : m_chatItems) {
+        for (const auto &c : m_chatItems) {
             stream << c.id;
             stream << c.name;
             stream << c.value;
diff --git a/gpt4all-chat/database.cpp b/gpt4all-chat/database.cpp
index 7ec2050a..1bb96115 100644
--- a/gpt4all-chat/database.cpp
+++ b/gpt4all-chat/database.cpp
@@ -125,12 +125,13 @@ bool removeChunksByDocumentId(QSqlQuery &q, int document_id)
 QStringList generateGrams(const QString &input, int N)
 {
     // Remove common English punctuation using QRegularExpression
-    QRegularExpression punctuation(R"([.,;:!?'"()\-])");
+    static QRegularExpression punctuation(R"([.,;:!?'"()\-])");
     QString cleanedInput = input;
     cleanedInput = cleanedInput.remove(punctuation);
 
     // Split the cleaned input into words using whitespace
-    QStringList words = cleanedInput.split(QRegularExpression("\\s+"), Qt::SkipEmptyParts);
+    static QRegularExpression spaces("\\s+");
+    QStringList words = cleanedInput.split(spaces, Qt::SkipEmptyParts);
     N = qMin(words.size(), N);
 
     // Generate all possible N-grams
@@ -147,7 +148,8 @@ QStringList generateGrams(const QString &input, int N)
 
 bool selectChunk(QSqlQuery &q, const QList<QString> &collection_names, const QString &chunk_text, int retrievalSize)
 {
-    const int N_WORDS = chunk_text.split(QRegularExpression("\\s+")).size();
+    static QRegularExpression spaces("\\s+");
+    const int N_WORDS = chunk_text.split(spaces).size();
     for (int N = N_WORDS; N > 2; N--) {
         // first try trigrams
         QList<QString> text = generateGrams(chunk_text, N);
@@ -730,7 +732,7 @@ void Database::addCurrentFolders()
         return;
     }
 
-    for (auto i : collections)
+    for (const auto &i : collections)
         addFolder(i.collection, i.folder_path);
 }
 
@@ -839,7 +841,7 @@ void Database::removeFolderInternal(const QString &collection, int folder_id, co
 
     // First remove all upcoming jobs associated with this folder by performing an opt-in filter
     QQueue<DocumentInfo> docsToScan;
-    for (DocumentInfo info : m_docsToScan) {
+    for (const DocumentInfo &info : m_docsToScan) {
         if (info.folder == folder_id)
             continue;
         docsToScan.append(info);
@@ -906,9 +908,11 @@ void Database::retrieveFromDB(const QList<QString> &collections, const QString &
     }
 
     while (q.next()) {
+#if defined(DEBUG)
         const int rowid = q.value(0).toInt();
-        const QString date = QDateTime::fromMSecsSinceEpoch(q.value(1).toLongLong()).toString("yyyy, MMMM dd");
+#endif
         const QString chunk_text = q.value(2).toString();
+        const QString date = QDateTime::fromMSecsSinceEpoch(q.value(1).toLongLong()).toString("yyyy, MMMM dd");
         const QString file = q.value(3).toString();
         const QString title = q.value(4).toString();
         const QString author = q.value(5).toString();
@@ -946,7 +950,7 @@ void Database::cleanDB()
         return;
     }
 
-    for (auto i : collections) {
+    for (const auto &i : collections) {
         // Find the path for the folder
         QFileInfo info(i.folder_path);
         if (!info.exists() || !info.isReadable()) {
@@ -1017,7 +1021,6 @@ void Database::changeChunkSize(int chunkSize)
 
     while (q.next()) {
         int document_id = q.value(0).toInt();
-        QString document_path = q.value(1).toString();
         // Remove all chunks and documents to change the chunk size
         QSqlQuery query;
         if (!removeChunksByDocumentId(query, document_id)) {
diff --git a/gpt4all-chat/download.cpp b/gpt4all-chat/download.cpp
index a8419fd8..90acecf9 100644
--- a/gpt4all-chat/download.cpp
+++ b/gpt4all-chat/download.cpp
@@ -74,7 +74,7 @@ QList<ModelInfo> Download::modelList() const
     ModelInfo bestLlamaInfo;
     ModelInfo bestMPTInfo;
     QList<ModelInfo> filtered;
-    for (ModelInfo v : values) {
+    for (const ModelInfo &v : values) {
         if (v.isDefault)
             defaultInfo = v;
         if (v.bestGPTJ)
@@ -310,7 +310,7 @@ void Download::removeModel(const QString &modelFile)
 void Download::handleSslErrors(QNetworkReply *reply, const QList<QSslError> &errors)
 {
     QUrl url = reply->request().url();
-    for (auto e : errors)
+    for (const auto &e : errors)
         qWarning() << "ERROR: Received ssl error:" << e.errorString() << "for" << url;
 }
 
@@ -658,7 +658,6 @@ void Download::handleReadyRead()
     if (!modelReply)
         return;
 
-    QString modelFilename = modelReply->url().fileName();
     QFile *tempFile = m_activeDownloads.value(modelReply);
     QByteArray buffer;
     while (!modelReply->atEnd()) {
diff --git a/gpt4all-chat/network.cpp b/gpt4all-chat/network.cpp
index 75167570..3c003973 100644
--- a/gpt4all-chat/network.cpp
+++ b/gpt4all-chat/network.cpp
@@ -153,15 +153,16 @@ void Network::handleJsonUploadFinished()
         sendHealth();
     }
 
+#if defined(DEBUG)
     QByteArray jsonData = jsonReply->readAll();
     QJsonParseError err;
+
     QJsonDocument document = QJsonDocument::fromJson(jsonData, &err);
     if (err.error != QJsonParseError::NoError) {
         qDebug() << "ERROR: Couldn't parse: " << jsonData << err.errorString();
         return;
     }
 
-#if defined(DEBUG)
     printf("%s\n", qPrintable(document.toJson(QJsonDocument::Indented)));
     fflush(stdout);
 #endif
@@ -172,7 +173,7 @@ void Network::handleJsonUploadFinished()
 void Network::handleSslErrors(QNetworkReply *reply, const QList<QSslError> &errors)
 {
     QUrl url = reply->request().url();
-    for (auto e : errors)
+    for (const auto &e : errors)
         qWarning() << "ERROR: Received ssl error:" << e.errorString() << "for" << url;
 }
 
@@ -421,7 +422,7 @@ void Network::sendMixpanelEvent(const QString &ev, const QVector<KeyValue> &valu
 #endif
     }
 
-    for (auto p : values)
+    for (const auto& p : values)
         properties.insert(p.key, p.value);
 
     QJsonObject event;
diff --git a/gpt4all-chat/server.cpp b/gpt4all-chat/server.cpp
index 87ba5cde..2a65546c 100644
--- a/gpt4all-chat/server.cpp
+++ b/gpt4all-chat/server.cpp
@@ -192,7 +192,7 @@ QHttpServerResponse Server::handleCompletionRequest(const QHttpServerRequest &re
             prompts.append(promptValue.toString());
         else {
             QJsonArray array = promptValue.toArray();
-            for (QJsonValue v : array)
+            for (const QJsonValue &v : array)
                 prompts.append(v.toString());
         }
     } else
diff --git a/gpt4all-chat/sysinfo.h b/gpt4all-chat/sysinfo.h
index 4a02826f..29a3b9bd 100644
--- a/gpt4all-chat/sysinfo.h
+++ b/gpt4all-chat/sysinfo.h
@@ -24,7 +24,8 @@ QString getSystemTotalRAM()
         QString line = in.readLine();
         while (!line.isNull()) {
             if (line.startsWith("MemTotal")) {
-                QStringList parts = line.split(QRegularExpression("\\s+"));
+                static QRegularExpression spaces("\\s+");
+                QStringList parts = line.split(spaces);
                 totalRAM = parts[1].toLongLong() * 1024; // Convert from KB to bytes
                 break;
             }