diff --git a/apps/openmw/mwmechanics/npcstats.cpp b/apps/openmw/mwmechanics/npcstats.cpp
index 39a5d68034..5367d31102 100644
--- a/apps/openmw/mwmechanics/npcstats.cpp
+++ b/apps/openmw/mwmechanics/npcstats.cpp
@@ -227,3 +227,13 @@ int MWMechanics::NpcStats::getLevelupAttributeMultiplier(int attribute) const
     else
         return 5;
 }
+
+void MWMechanics::NpcStats::flagAsUsed (const std::string& id)
+{
+    mUsedIds.insert (id);
+}
+
+bool MWMechanics::NpcStats::hasBeenUsed (const std::string& id) const
+{
+    return mUsedIds.find (id)!=mUsedIds.end();
+}
diff --git a/apps/openmw/mwmechanics/npcstats.hpp b/apps/openmw/mwmechanics/npcstats.hpp
index 7c3055783d..48e63d7b6e 100644
--- a/apps/openmw/mwmechanics/npcstats.hpp
+++ b/apps/openmw/mwmechanics/npcstats.hpp
@@ -50,6 +50,8 @@ namespace MWMechanics
 
             std::vector<int> mSkillIncreases; // number of skill increases for each attribute
 
+            std::set<std::string> mUsedIds;
+
         public:
 
             NpcStats();
@@ -86,6 +88,10 @@ namespace MWMechanics
             int getLevelupAttributeMultiplier(int attribute) const;
 
             void levelUp();
+            
+            void flagAsUsed (const std::string& id);
+            
+            bool hasBeenUsed (const std::string& id) const;
     };
 }