[UnFleshedOne]

Another reason to use a library is once you write that left pad function yourself, you have to go copy it around from project to project whenever you need it, then fix or improve it and copy the changes all over again. Second time you do that, might as well pull it into a library. And now you have a library that you lug around, might as well host it somewhere. In a few short decades you roll your own package management infrastructure and fill it with all kinds of useful things like string concatenation subroutines and macros for flow control primitives built on jmp instructions and stuff like that.

Might as well shortcut all that and see if there is something in standard library or in an existing package...