diff --git a/modules/common/nix.nix b/modules/common/nix.nix
index fe044a8..0fe1893 100644
--- a/modules/common/nix.nix
+++ b/modules/common/nix.nix
@@ -16,6 +16,8 @@
         max-silent-time = 3600;
         timeout = 0;
 
+        auto-optimise-store = true;
+
         # Package caches
         substituters = [
           "https://cache.nixos.org"