Evaluating information is not an either/or decision. Instead, the decision of whether or not to use a resource, or particular piece of information is up to you, dependent on what you need it for and how you're using it.
Use the variety of criteria on this page to pick the best information for your purpose, and note that different criteria are better suited to certain types of sources.
Be critical of every web page and piece of information you find. Use one of these checklists to make sure you've really looked closely at a website you're considering citing.
Authority / Reliability / Credibility