diff --git a/README.md b/README.md
index c94d593..0b29f27 100644
--- a/README.md
+++ b/README.md
@@ -6,3 +6,12 @@ necessary to set up a gentoo github mirror based sync system:
 * updates the glsa directory
 * updates herds.xml
 * updates the news directory
+
+## Notes
+
+Note that typically most repositories other than `gentoo` don't come with a pregenerated cache. It is a good idea to generate/update their cache every time they are synced. One way to do this, is by activating the `example` hook script that portage installs by default in /etc/portage/postsync.d:
+
+```
+cp -i /etc/portage/repo.postsync.d/example /etc/portage/repo.postsync.d/gen_cache
+chmod +x /etc/portage/repo.postsync.d/gen_cache
+```