diff --git a/modules/common.nix b/modules/common.nix
index 5afec68..55df1ee 100755
--- a/modules/common.nix
+++ b/modules/common.nix
@@ -15,6 +15,12 @@
     trusted-users = [ "@wheel" ];
   };
 
+  nix.gc = {
+    automatic = true;
+    dates = "weekly";
+    options = "--delete-older-than 30d";
+  };
+
   users.users.nettika = {
     isNormalUser = true;
     extraGroups = [ "wheel" "networkmanager" ];