howto/upgrades.md

@@ -159,7 +159,14 @@ You can see the latest output of that job with:
 Normally, the package lists are updated automatically by that job, if
 the `APT::Periodic::Update-Package-Lists` setting (typically in
 `/etc/apt/apt.conf.d/10periodic`, but it could be elsewhere in
-`/etc/apt/apt.conf.d`) is set to 1.
+`/etc/apt/apt.conf.d`) is set to 1. See the config dump in:
+
+    apt-config dump | grep APT::Periodic::Update-Package-Lists
+
+Note that `1` does not mean "true" in this case, it means "one day",
+which could introduce extra latency in the reboot procedure. Use
+`always` to run the updates every time the job runs. See [issue
+22](https://gitlab.torproject.org/tpo/tpa/prometheus-alerts/-/issues/22).
 
 Before the transition to Prometheus, NRPE checks were also running
 updates on package lists, it's possible the retirement might have