diff --git a/input/models.py b/input/models.py
index b798ef8..6dff1dc 100644
--- a/input/models.py
+++ b/input/models.py
@@ -38,7 +38,8 @@ class Extern(Volunteer):
     service_id = models.CharField(max_length=15, null=True, blank=True)
 
     def save(self,*args,**kwargs):
-        # is there a way to call super().save() only once?
+        # we don't call save with args/kwargs to avoid UNIQUE CONSTRAINT errors
+        # but maybe there is a better solution?
         super().save()
         self.service_id = type(self).__name__ + str(self.pk)
         super().save()
@@ -89,9 +90,13 @@ class Project(Volunteer):
 
     def save(self,*args,**kwargs):
         '''we generate the autogenerated fields here'''
+        # we don't call save with args/kwargs to avoid UNIQUE CONSTRAINT errors
+        # but maybe there is a better solution?
         super().save()
         self.pid = str(self.account.code) + str(self.pk).zfill(3)
+        # generation of finance_id
         if not self.project_of_year:
+            # we need to determine if this is a new year with its first new project...
             year = self.start.year
             projects = Project.objects.filter(start__year=year)
             if not projects: