Scott Langdon with HighVisability and Entrepreneur magazine wrote an article about five different tools you can use to audit the quality of the content on your site. It is suggested to do this every six months. We include this service in our SEO package as well.
The main points Langdon says you should look out for include:
The tools he mentions that we also use include:
1. Screaming Frog
2. Online XML Sitemap Generator
3. Google Analytics Content Reports
4. Open Site Explorer
To read more, to the the following article from Entrepreneur magazine: