Automated Testing Question:

Automation is the integration of testing tools into the test environment in such a manner that the test execution, logging, and comparison of results are done with little human intervention. A testing tool is a software application which helps automate the testing process. But the testing tool is not the complete answer for automation. One of the huge mistakes done in testing automation is automating the wrong things during development. Many testers learn the hard way that everything cannot be automated. The best components to automate are repetitive tasks. So some companies first start with manual testing and then see which tests are the most repetitive ones and only those are then automated.

As a rule of thumb do not try to automate:

Unstable software: If the software is still under development and undergoing many changes automation testing will not be that effective.
Once in a blue moon test scripts: Do not automate test scripts which will be run once in a while.
Code and document review: Do not try to automate code and document reviews; they will just cause trouble.