Using dup contet, will it hurt in the long run?

[Walalayo]

If I am using general articles that are found on many websites on the web as initial content on my site, but then slowly start adding original content, will the pages with original content suffer at all from the duplicate content? Assume that for one reason or another I have to allow googlebot onto the site to crawl the duplicate content.

Also, will it hurt the site's rankings on the main page by using duplicate content on the article pages?

Please let me know what you think, thanks!