Some facts and ideas are so well-known that they are considered to be common knowledge and do not need to be cited.
SPARK at York University (2013) suggests the following guidelines when you are considering whether to cite, or not:
1. If in doubt, cite
2. Always cite arguments, foundational texts and controversial information.
3. Seek advice from your instructor for further clarification.
For more information please visit SPARK's What is Common Knowledge? guidelines.
According to the APA Manual, 7th edition, overcitation (or too many in-text citations for the same source) can be "distracting and unnecessary" (p. 254).
An example of overcitation is to repeat the same citation in every sentence when the source and topic have not changed:
Lambert (2018) states that websites dedicated to journalism need visitors to survive. Two things that a website needs to do is to attract visitors, and then keep them there once they have visited (Lambert, 2018).
Paraphrasing Over Multiple Sentences
When paraphrasing a work over multiple sentences, rather than include a citation in every sentence, the APA manual recommends citing the source in the first sentence only, and not repeating the citation as long as the source remains clear and unchanged.
Example:
Lambert (2018) states that websites dedicated to journalism need visitors to survive. Two things that a website needs to do is to attract visitors, and then keep them there once they have visited. A process called "search engine optimization" can be used in order to push results from your website up in the Google search results.
Using the Author's Name in the Narrative
If you are citing from the same source within a paragraph and using the author's name in the narrative, you can omit the year.
Example:
Lambert (2018) states that websites dedicated to journalism need visitors to survive. According to Lambert, two things that a website needs to do is to attract visitors, and then keep them there once they have visited.