You must use citations when:
WHEN IN DOUBT, CITE IT!
The joy of finding footnotes and bibliographic entries that lead to the perfect original source can only happen when scholars carefully track their sources and generate citations in an appropriate style. Neglecting to track your sources as you move through the research process will cost you HOURS of precious time.
Try Zotero, a free, easy-to-use tool to help you collect, organize, cite, and share your research sources.