Before you add it to your site, you first have to decide whether it would be a benefit. Does it make your site look professional? Does that matter? If your site is recreation or hobby oriented, then AdSense won’t really detract from anything. It is a less formal setting in the first place. On the other hand, if it’s a company site, AdSense tends to look amateur. Companies would be better served setting up direct advertising partnerships.

If you can first decide the purpose of your site, you’ll be on your way to deciding if Google AdSense is right for you.