Where to include css and js files on a web application [on hold]

I am working on a web application, and tend to include javascript and CSS files on my base template if it is used by more than one page for the sake of convenience, so I won't run into 'missing dependency' issue on my commonly used external files. However, that kind of bloats my base template, and I worry about its performance on the first load. I have not deployed my application and thus have not tested in real life cases.

So, I wonder if there are common practices, whether to include such files in base template, or in individual pages?