The structure of your website:
Maintain this structure
It is beneficial when your website expands naturally: returning visitors are regularly provided with new information and search engines will give growing websites a better score. Keep your website from becoming messy and maintain the 3-layer structure.
Use internal links wisely
When referring to information situated elsewhere on your website, provide a link, but keep your visitors from getting lost. Here Breadcrumbs can be a useful navigational aid.
Next blog post: structure of your website: what NOT to do