People usually need information for a particular purpose. So what kind of information is needed may vary depending upon the purpose. For a particular source, is the information provided relevant to what you need for your topic?
Do you need a broad overview of your topic? Perhaps it is new to you and you wish to start out with a working knowledge of the topic. In this case, you might be seeking sources which contribute to a Big Picture of the subject. I can't be a specialist on everything so I try to obtain at least a working knowledge on many subjects.
Do you need detailed information on your topic? You may have an assignment where you have to dig down into a topic. Or as a student, you may be required to become familiar with the scholarly discussion of your chosen major (in other words, what are the professionals in your discipline saying about this topic). In this case, you will need to find more detailed, in depth information and the language of the sources will be more specialized and advanced.
You may need to consider your audience. If you are a physician gathering information to help a patient understand their health condition, you would look for information at a reading level appropriate to your patient. If you are a professor studying a research topic to share with other researchers, you would look for other research written at a language level accepted and appreciated by researchers specializing in that topic.
