diff --git a/common/misc.nix b/common/misc.nix
index af95d1b..3061e72 100644
--- a/common/misc.nix
+++ b/common/misc.nix
@@ -5,6 +5,7 @@
     automatic = true;
     dates = "weekly";
     randomizedDelaySec = "45min";
+    options = "--delete-older-than 30d";
   };
   nix.optimise.automatic = true;
   services.fstrim.enable = true;