You should really evaluate every source you plan to use in your paper or project to make sure it is appropriate. One method mentioned in the FYE class here at Sullivan is the CRAAP test developed by the librarians at CSU - Chico. The criteria in the CRAAP test are:
If you need more questions to ask yourself try the CSU Chico sheet explaining the CRAAP test below. Still aren't sure a source is reliable? Ask a librarian. We can help you evaluate a resource or point you toward another credible source if necessary.
Evaluation isn't just a step before you begin writing your paper. You should be constantly evaluating the information you have found as you go.