You should absolutely be using existing frameworks, libraries, and common practices. But a popular framework will allow you make any application imaginable. I

You should absolutely be using existing frameworks, libraries, and common practices. But a popular framework will allow you make any application imaginable. If you're not making radically different applications every day, you can extend and constrain existing frameworks with your own code to make them specific to your needs. For example, all my applications have the same look and feel, corporate branding, and authentication features. We use a popular framework but extended it to handle all of this stuff so it's never repeated between projects.