If the "modules" are source code you don't know or can't control, then it's a dependency that can create dependency headaches. For example, a new OS or browser

If the "modules" are source code you don't know or can't control, then it's a dependency that can create dependency headaches. For example, a new OS or browser version comes out and the existing components are not compatible with the upgrade. Happens all the time. External components are thus not a free lunch. What's really missing is the willingness to say "no". There's pressure to put fancy or trendy toys into applications to look up to date or to get experience on the latest fads. KISS and YAGNI are often ignored for eye candy or Fear of Falling Behind. For example, fairly early in the 2000's I had a web form that only did server-side date validation. It worked just fine. But client-side date validation was becoming "expected" because everyone started doing it and the manager asked me to put it in. So I found a JavaScript component on the web, and it worked fine at first. But a few months later a bug was found in it that appeared on a certain date, and it generated a lot of phone calls from users. Those phone calls would have never existed had I gone with my gut and left it out. Few users are going to spend all day making date errors such that client-side date validation is NOT necessary. It's a me-too toy. Warren Buffett often cites his ability to say "no" as to why he's so wealthy. He looks at the actual tradeoff numbers, not peer pressure.