Having to ask your colleague is an extra cost - for common tasks (like the example of parsing of command line arguments used in the parent comment) you should b

Having to ask your colleague is an extra cost - for common tasks (like the example of parsing of command line arguments used in the parent comment) you should be using the exact same code as your colleagues unless there is a good reason to make an exception (which there rarely is), so you should be able to read and maintain others' code just as yours because it's written in the same way as you would, making the same style of calls to the exact same functions. And furthermore, the third party libraries (at least for Python) are so standard that a new hire would have used the exact same library if they ever had to do the same task - for most things there's going to be just a few reasonable ways (and often just a single idiomatic one) to do that thing in the language, which sometimes used a built-in library and sometimes uses a popular third-party library. If your company has a dozen tools which need the same functionality, "rolling your own" for each codebase (or worse, copy/pasting it without being able to update them from a single place) is obviously not a good solution - the choice is between making and using an internally maintained library, or using an open source one.