Minimal, I have to force myself to check the servers for updates atleast once a week.
Main problem for me is I automated podman and docker updates with their respective autoupdate mechanisms and use ntfy for push notifications so I know if a service stops working and I had an update recently on it that it's an update issue.
Also have uptime monitor wih uptime kuma to monitor state of my services to catch them not working before I do, also ntfy for push notifications.
Also have grafana+prometheus seted up on my biggest server for monitoring and alerting with alertmanager+mail to get notifications on even more errors.
So in general I only have to worry about occasional once every few months error and updates of the host system (debian).