I’ll do system updates at least one time in a week, most notably to get more recent version of software installed. My zbox is powered by an Arch Linux installation, which does a fantastic job. Very reliable and fast. In the past I used yaourt (inofficial frontend to Arch’s package manager pacman) to update the system by using yaourt -Syu but this only updates the packages that are inside the official repositories, not the packages that are in AUR. AUR packages were updated with this syntax some time ago as well, but now I have to use yaourt -Syua to do the job.