A sysadmin is like a member of the pit crew at the Formula One races. Don't admit anyone who is under-qualified, lacking practical experience and education. I

A sysadmin is like a member of the pit crew at the Formula One races. Don't admit anyone who is under-qualified, lacking practical experience and education. I carry a notebook (dead-tree version) and take copious notes of before and after states, note each step taken and ALWAYS backup configuration files before changing them. Where applicable I snapshot configurations before and after listing, etc to a directory for that session. If you are using service/consulting firms, watch-out! Over time they will send ever less experienced staff in their attempt to rack up profits. It never ends well. Eventually a simple mistake takes out a critical part of your infrastructure and they'll assign blame to some absolutely incredible and unrelated factor.