diff --git a/bluemaestro/__init__.py b/bluemaestro/__init__.py
index ee000bc..55974b8 100755
--- a/bluemaestro/__init__.py
+++ b/bluemaestro/__init__.py
@@ -18,14 +18,18 @@ def get_logger():
     return logging.getLogger('bluemaestro')
 
 
-def get_temperature():
+def get_temperature(all_=False):
     logger = get_logger()
-    merged: Dict[datetime, Any] = {}
 
-    for f in list(sorted(chain(
+    backups = list(sorted(chain(
             DIR.glob('*.db'),
             DIR2.glob('*.db'),
-    ))):
+    )))
+    if not all_:
+        backups = [backups[-1]]
+
+    merged: Dict[datetime, Any] = {}
+    for f in backups:
         def reg(dt: datetime, value):
             v = merged.get(dt, None)
             if v is None:
@@ -68,6 +72,9 @@ def get_temperature():
     #         print(k, v)
     return merged
 
+def test():
+    get_temperature(all_=False)
+
 def main():
     setup_logzero(get_logger(), level=logging.DEBUG)
     get_temperature()
diff --git a/bluemaestro/check.py b/bluemaestro/check.py
index 028d6d0..34861a6 100755
--- a/bluemaestro/check.py
+++ b/bluemaestro/check.py
@@ -8,17 +8,23 @@ from my.bluemaestro import get_temperature, get_logger
 def main():
     setup_logzero(get_logger(), level=logging.DEBUG)
 
-    temps = get_temperature()
+    temps = get_temperature(all_=False)
     latest = sorted(temps.items())[:-2]
 
     prev, _ = latest[-2]
     last, _ = latest[-1]
+
+    POINTS_STORED = 6000
+    FREQ_SEC = 60
+    SECS_STORED = POINTS_STORED * FREQ_SEC
+    HOURS_STORED = POINTS_STORED / (60 * 60 / FREQ_SEC) # around 4 days
+    NOW = datetime.now()
+    assert NOW - last < timedelta(hours=HOURS_STORED / 2), f'old backup! {last}'
+
+
     assert last - prev  < timedelta(minutes=3), f'bad interval! {last - prev}'
     single = (last - prev).seconds
 
-    NOW = datetime.now()
-    assert NOW - last < timedelta(days=2), f'old backup! {last}'
-    # TODO change to 1 later?
 
 
 if __name__ == '__main__':