A stupid SEO question. I have a site that is ranking in the number two spot on Google. I haven't made any changes to the site in several weeks. I'm kind of afraid to make changes or add anything because I'm afraid it will affect the ranking, but then I know that if I don't add new content it will become stale and Google may drop the ranking for that reason. Is there a rule of thumb for how often a website should be updated? And should I mess with a site that is receiving such good ranking?
I don't think so If you update your page google will drop your ranking. Google always loves fresh content and changes.
There is a difference between changing a site & adding new content. Adding fresh content will give your site more relevance & authority in Google. So do it often.