  Writing functions in R is an important skill for anyone using R. S3 methods
allow for functions to be generalised across different classes and are easy to
implement. Whilst many R users are be adept at creating their own functions, it
seems that there is room for many more to take advantage of R's S3 methods.
This paper provides a simple and targeted guide to explain what S3 methods are,
why people should them, and how they can do it.
