Use an actual quote when it has just the thought you want and when the person who said it lends authority. Otherwise, feel free to paraphrase. Attribute a quote any time it seems right to give a source. They can emphasize a point, pour some pepper into a sentence. Without plagiarizing, you could take a hundred quotes, jokes and anecdotes on a subject and create an article.
People sometimes find a difficult message easier to swallow when it is couched in a quote.