I'm beginning to develop a heuristic around the concept of "amount of the library you use". It's intrinsically fuzzy and still something I'm working on, but in general, it's bad to use only a tiny fraction of a library or framework, and really bad to have a code base in which a large number of things are pulled in that you only use small fractions of.

There are some exceptions, e.g., pulling in your languages best-of-breed image library to load some JPGs even though it supports literally a dozen other formats is less disastrous to a code base than pulling in an industrial-strength web framework just to provide two API calls with some basic auth of some sort. But there's something to the concept in general, I think.