When was the material created?
In some disciplines, such as new technologies, information can become outdated very quickly. In other fields, like literature or history, sources that are decades old may still be valid. Consider your area of study and consult related sources to determine the timeliness of a source and how that impacts it value to you.
Where to find
Most articles, whether popular or scholarly, and books will list the date of publication at the beginning of the source.
Websites may have this information, commonly found at the top or bottom of the page.
