A Quote From Essential System Administration 3rd Edition

My philosophy of system administration boils down to a few basic strategies that can be applied to virtually any of its component tasks:
* Know how things work. In these days, when operating systems are marketed as requiring little or no system administration, and the omnipresent simple-to-use tools attempt to make system administration simple for an uninformed novice, someone has to understand the nuances and details of how things really work. It should be you.* Plan it before you do it.* Make it reversible (backups help a lot with this one).* Make changes incrementally.* Test, test, test, before you unleash it on the world.
Æleen Frisch -- Essential System Administration 3rd Edition