Using a custom library in R

I’ve been using a custom library for R since 2012 and I’ve never looked back. I’ve not seen many tutorials for people do do this through R, so I figured I’d write a quick one. Where does your R package library live? You can usually find this out by typing .libPaths() in your R console. If you have an out-of-the-box installation, it will generally be somewhere like: C:/Program Files/R/R-3.