diff --git a/autotests/libs/mimetypecheckertest.cpp b/autotests/libs/mimetypecheckertest.cpp
--- a/autotests/libs/mimetypecheckertest.cpp
+++ b/autotests/libs/mimetypecheckertest.cpp
@@ -55,6 +55,7 @@
     const QLatin1String textPlain = QLatin1String("text/plain");
     mEmptyChecker.addWantedMimeType(textPlain);
     QVERIFY(!mEmptyChecker.wantedMimeTypes().isEmpty());
+    QVERIFY(mEmptyChecker.hasWantedMimeTypes());
 
     const QLatin1String textCalendar = QLatin1String("text/calendar");
     calendarChecker.addWantedMimeType(textCalendar);
@@ -74,6 +75,7 @@
     mAliasChecker    = aliasChecker;
 
     QVERIFY(mEmptyChecker.wantedMimeTypes().isEmpty());
+    QVERIFY(!mEmptyChecker.hasWantedMimeTypes());
 
     QCOMPARE(mCalendarChecker.wantedMimeTypes().count(), 1);
     QCOMPARE(mCalendarChecker.wantedMimeTypes(), QStringList() << textCalendar);
diff --git a/src/core/mimetypechecker.h b/src/core/mimetypechecker.h
--- a/src/core/mimetypechecker.h
+++ b/src/core/mimetypechecker.h
@@ -135,10 +135,22 @@
     /**
      * Returns the list of wanted MIME types this instance checks against.
      *
-     * @see setWantedMimeTypes()
+     * @note Don't use this just to check whether there are any wanted mimetypes.
+     * It is much faster to call @c hasWantedMimeTypes() instead for that purpose.
+     *
+     * @see setWantedMimeTypes(), hasWantedMimeTypes()
      */
     QStringList wantedMimeTypes() const;
 
+    /**
+     * Checks whether any wanted MIME types are set.
+     *
+     * @return @c true if any wanted MIME types are set, false otherwise.
+     *
+     * @since 5.6.43
+     */
+    bool hasWantedMimeTypes() const;
+
     /**
      * Sets the list of wanted MIME types this instance checks against.
      *
diff --git a/src/core/mimetypechecker.cpp b/src/core/mimetypechecker.cpp
--- a/src/core/mimetypechecker.cpp
+++ b/src/core/mimetypechecker.cpp
@@ -54,6 +54,11 @@
     return d->mWantedMimeTypes.values();
 }
 
+bool MimeTypeChecker::hasWantedMimeTypes() const
+{
+    return !d->mWantedMimeTypes.isEmpty();
+}
+
 void MimeTypeChecker::setWantedMimeTypes(const QStringList &mimeTypes)
 {
     d->mWantedMimeTypes = QSet<QString>::fromList(mimeTypes);
diff --git a/src/core/models/entitytreemodel_p.cpp b/src/core/models/entitytreemodel_p.cpp
--- a/src/core/models/entitytreemodel_p.cpp
+++ b/src/core/models/entitytreemodel_p.cpp
@@ -471,7 +471,7 @@
         if (m_itemPopulation == EntityTreeModel::ImmediatePopulation) {
             foreach (const Collection::Id &collectionId, collectionIt.value()) {
                 const auto col = m_collections.value(collectionId);
-                if (m_mimeChecker.wantedMimeTypes().isEmpty() || m_mimeChecker.isWantedCollection(col)) {
+                if (!m_mimeChecker.hasWantedMimeTypes() || m_mimeChecker.isWantedCollection(col)) {
                     fetchItems(m_collections.value(collectionId));
                 } else {
                     // Consider collections that don't contain relevant mimetypes to be populated
@@ -521,8 +521,7 @@
             continue;
         }
 
-        if ((m_mimeChecker.wantedMimeTypes().isEmpty() ||
-                m_mimeChecker.isWantedItem(item))) {
+        if ((!m_mimeChecker.hasWantedMimeTypes() || m_mimeChecker.isWantedItem(item))) {
             // When listing virtual collections we might get results for items which are already in
             // the model if their concrete collection has already been listed.
             // In that case the collectionId should be different though.
@@ -773,7 +772,7 @@
     }
 
     //We're explicitly monitoring collections, but didn't match the filter
-    if (m_mimeChecker.wantedMimeTypes().isEmpty() && !m_monitor->collectionsMonitored().isEmpty()) {
+    if (!m_mimeChecker.hasWantedMimeTypes() && !m_monitor->collectionsMonitored().isEmpty()) {
         //The collection should be included if one of the parents is monitored
         if (isAncestorMonitored(collection)) {
             return true;
@@ -783,8 +782,7 @@
 
     // Some collection trees contain multiple mimetypes. Even though server side filtering ensures we
     // only get the ones we're interested in from the job, we have to filter on collections received through signals too.
-    if (!m_mimeChecker.wantedMimeTypes().isEmpty() &&
-            !m_mimeChecker.isWantedCollection(collection)) {
+    if (m_mimeChecker.hasWantedMimeTypes() && !m_mimeChecker.isWantedCollection(collection)) {
         return false;
     }
 
@@ -1081,8 +1079,7 @@
 
     Q_ASSERT(m_collectionFetchStrategy != EntityTreeModel::InvisibleCollectionFetch ? m_collections.contains(collection.id()) : true);
 
-    if (!m_mimeChecker.wantedMimeTypes().isEmpty() &&
-            !m_mimeChecker.isWantedItem(item)) {
+    if (m_mimeChecker.hasWantedMimeTypes() && !m_mimeChecker.isWantedItem(item)) {
         return;
     }
 
@@ -1271,8 +1268,7 @@
 
     Q_ASSERT(m_collections.contains(collectionId));
 
-    if (!m_mimeChecker.wantedMimeTypes().isEmpty() &&
-            !m_mimeChecker.isWantedItem(item)) {
+    if (m_mimeChecker.hasWantedMimeTypes() && !m_mimeChecker.isWantedItem(item)) {
         return;
     }
 
@@ -1485,7 +1481,7 @@
         m_collections.insert(m_rootCollection.id(), m_rootCollection);
     }
 
-    const bool noMimetypes = m_mimeChecker.wantedMimeTypes().isEmpty();
+    const bool noMimetypes = !m_mimeChecker.hasWantedMimeTypes();
     const bool noResources = m_monitor->resourcesMonitored().isEmpty();
     const bool multipleCollections = m_monitor->collectionsMonitored().size() > 1;
     const bool generalPopulation = !noMimetypes || (noMimetypes && noResources);