I'm currently trying to setup an authority website with a friend in a small, but growing niche. We both have full time jobs, however are both interested in progressing with this site due to having a shared interest in it. One of the things we're looking into is content writers, to write pieces such as guides or news stories, taking content from various sources and rehashing it into our own, fully unique content. Is this something many do, or for an authority site, it is not recommended? I want this content to be unique and targeted for our website, which does require knowledge in the area. The last thing I want to do is to hurt future rankings because the content doesn't add value.