First if all, I don&#x27;[t think it is a good idea to let developers get away with just including any random library they feel like. Part of your code review should be to check the build,gradle, pom.xml or Makefile to make sure that added libraries are thought through.<p>Some libraries are targeted on doing one job well and using them is a great idea. But other like scalaz are hugely filled with implications, not the least of which is to UNDERSTAND how to effectively use it.<p>I don&#x27;t use scalaz at all, not because I don&#x27;t believe in functional programming, but because I believe in Scala functional programming and I want to make sure that I write code that other Scala developers can understand.<p>I&#x27;m not saying that scalaz is bad or good. It&#x27;s just that it is a big deal and the whole team needs to drink the koolaid to get a real benefit. You could say the same about Apache Camel which is a wonderful tool that more people should use, but when you see it tucked into only one class of an app with roughly 100 classes, you wonder what is the point. Akka is the same kind of thing. You either embrace something like that or you avoid it. And make sure that everyone in the team is involved in the discussion.