Oh yes, my Avast is automatic but with the volume set to a bearable level, still makes me jump if I'm deep into whatever I'm doing though
As for general policy with updates I follow a routine that I've been using for years.
One thing from working with servers that I've found useful in these days of leaving machines on 24/7 is I always reboot the machine before
I install anything major. That way you know if you can't boot after the install it's definitely caused by the update, and not something I tweaked a week ago
. I always re-boot after a major install even if it's not requested for the same reason