diff --git a/objets.py b/objets.py
index 6867dc9..9ea3acc 100644
--- a/objets.py
+++ b/objets.py
@@ -66,7 +66,7 @@ import cranslib.deprecated
 
 #: Champs à ignorer dans l'historique
 HIST_IGNORE_FIELDS = ["modifiersName", "entryCSN", "modifyTimestamp", "historique"]
-FACTURES_REFRESH_PERIOD = 5
+FACTURES_REFRESH_PERIOD = 60
 
 def new_cransldapobject(conn, dn, mode='ro', uldif=None, lockId=None):
     """Crée un objet :py:class:`CransLdapObject` en utilisant la classe correspondant à
@@ -1041,7 +1041,7 @@ class proprio(CransLdapObject):
         """Retourne la date de fin d'adhésion"""
         return max([
             float(facture.get('finAdhesion', [crans_utils.from_generalized_time_format(attributs.finAdhesion.default)])[0])
-            for facture in self.factures(refresh=True, mode="ro")
+            for facture in self.factures(refresh=(time.time() - self._factures_last_update > FACTURES_REFRESH_PERIOD))
             if facture.get('controle', [''])[0] != u"FALSE" and facture.get('recuPaiement', [''])[0] != ''
         ] + [0.0])
 
@@ -1055,7 +1055,7 @@ class proprio(CransLdapObject):
         """Retourne la date de fin de connexion"""
         return max([
             float(facture.get('finConnexion', [crans_utils.from_generalized_time_format(attributs.finConnexion.default)])[0])
-            for facture in self.factures(refresh=True, mode="ro")
+            for facture in self.factures(refresh=(time.time() - self._factures_last_update > FACTURES_REFRESH_PERIOD))
             if facture.get('controle', [''])[0] != u"FALSE" and facture.get('recuPaiement', [''])[0] != ''
         ] + [0.0])
 
@@ -1142,7 +1142,7 @@ class proprio(CransLdapObject):
         if self._factures:
             if self._factures[0].mode != mode:
                 refresh = True
-        if self._factures is None or (refresh and time.time() - self._factures_last_update > FACTURES_REFRESH_PERIOD):
+        if self._factures is None or refresh:
             try:
                 self._factures = self.conn.search(u'fid=*', dn=self.dn, scope=1, mode=mode)
                 for m in self._factures: