diff --git a/src/Mulkup/Main.hs b/src/Mulkup/Main.hs
index 3b080c4..829ef5d 100644
--- a/src/Mulkup/Main.hs
+++ b/src/Mulkup/Main.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE UndecidableInstances #-}
 
@@ -6,14 +5,13 @@
 
 import Colog (Message, richMessageAction, simpleMessageAction)
 import Colog.Polysemy.Effect (Log, runLogAction)
-import qualified Data.List.NonEmpty as NonEmpty
 import qualified Data.Set as Set
-import Data.Time
 import Mulkup.Bupstash
 import Mulkup.Config
 import Mulkup.Flags
 import Mulkup.Logging
 import Mulkup.Prelude
+import Mulkup.Ranking
 import Optics
 import Options.Applicative
   ( execParser,
@@ -59,24 +57,7 @@
 
     currentItems <- bupList (BupFilter labels Nothing)
 
-    let tiers =
-          [ (utctHour . bupItemUTCTime, #hourly),
-            (utctJulianDay . bupItemUTCTime, #daily),
-            (utctWeek . bupItemUTCTime, #weekly),
-            (utctMonth . bupItemUTCTime, #monthly)
-          ]
-
-    let keepIds =
-          Set.unions $
-            map
-              ( \(discriminator, cfgLens) ->
-                  let tierCfg = stash ^. #tiers ^. cfgLens
-                   in tierKeepIds discriminator (tierCfg ^. #keep) currentItems
-              )
-              tiers
-
-    let currentIds = Set.fromList (map (^. #id) currentItems)
-    let rmIds = Set.difference currentIds keepIds
+    let (keepIds, rmIds) = rankBupItems (stash ^. #tiers) currentItems
 
     logInfo (show labels <> " Keeping: " <> show (Set.toList keepIds))
     logInfo (show labels <> " Removing: " <> show (Set.toList rmIds))
@@ -87,32 +68,3 @@
       (stash ^. #baseDir)
       (stash ^. #exclusions)
       labels
-
-tierKeepIds :: (BupItem -> Integer) -> Natural -> [BupItem] -> Set Text
-tierKeepIds discriminator keep items =
-  fromList $
-    take (fromIntegral keep) $
-      map (^. #id) $
-        reverse $
-          sortWith bupItemUTCTime $
-            map (head . NonEmpty.sortWith bupItemUTCTime) $
-              elems $
-                (groupBy discriminator items :: HashMap Integer (NonEmpty BupItem))
-
-utctHour :: UTCTime -> Integer
-utctHour (UTCTime (ModifiedJulianDay julianDay) tdiff) = (julianDay * 24) + (diffTimeToPicoseconds tdiff `div` (10 ^ (12 :: Integer)) `div` 3600)
-
-utctJulianDay :: UTCTime -> Integer
-utctJulianDay (UTCTime (ModifiedJulianDay julianDay) _) = julianDay
-
-utctWeek :: UTCTime -> Integer
-utctWeek (UTCTime day _) =
-  julianDay + fromIntegral (dayOfWeekDiff (dayOfWeek day) Sunday)
-  where
-    (ModifiedJulianDay julianDay) = day
-    dayOfWeekDiff a b = mod (fromEnum a - fromEnum b) 7
-
-utctMonth :: UTCTime -> Integer
-utctMonth (UTCTime day _) = fromIntegral m
-  where
-    (_, m, _) = toGregorian day