Thanks to the internet, literature searches are now relatively easy, and can be done from the comfort of your own laptop without needing to go anywhere near a library. The ease with which anybody can access and publish to the internet means that many items published online have not been scrutinised by anybody other than the author.
However, be aware that some professionals may find constant requests for information intrudes on their time.
Always be courteous and sensitive to the level of demand you may be making on someone’s time.
Librarians are usually hugely experienced in using all the search tools and databases, and can often show you much quicker ways of doing things, as well as tips and tricks to help you refine your search.
Furthermore, libraries may have copies of books and academic journals that are not available online.