diff --git a/odoo/backups/plan.py b/odoo/backups/plan.py
index b24b098..e3f07c4 100644
--- a/odoo/backups/plan.py
+++ b/odoo/backups/plan.py
@@ -12,9 +12,12 @@ Keep :
 """
 
 from datetime import datetime
-from os import unlink
+from os import unlink, environ
 from glob import glob
 
+OBPLAN = environ.get('OBPLAN', u'365,31,7')
+OBPLAN = map(int, OBPLAN.split(u','))
+
 DT = datetime.now()
 
 def notkeep(fname):
@@ -26,12 +29,12 @@ def notkeep(fname):
     save_date = fname[0]
     save_date = datetime.strptime(save_date, '%Y-%m-%d')
     delta = DT - save_date
-    if delta.days > 365:
+    if delta.days > OBPLAN[0]:
         return True
-    elif delta.days > 31:
+    elif delta.days > OBPLAN[1]:
         if save_date.day != 1:
             return True
-    elif delta.days > 7:
+    elif delta.days > OBPLAN[2]:
         if (save_date.weekday() != 0) and (save_date.day != 1):
             return True
     else: