Automate build, test, and install processes.
Automate dull, tedious, or repetitive work
Automate to free time for creative, intellectual work. 
Never automate evolving processes.
Do not automate in order to avoid human interaction. 
Prefer physical artifacts with coercive immediacy 
Software serves the team, never the reverse.

http://agileinaflash.blogspot.com/2009/02/automating-tasks.html