Package functions for reuse
Pulling out the major parts of your scripts as separate functions has the advantage that you can more easily reuse that code.
But functions sitting deep within some project directory are not likely
to be used again. (“It’s in a file called
func.R, but which
project was I working on?”)
When possible, package up those useful functions as a stand-alone thing. This will make it easier for you (and others) to reuse them. It’s also a good opportunity to document those functions.
Writing R packages is really not so hard as one might think. See my R package primer, Hadley Wickham’s R packages book, or Hilary Parker’s tutorial on R packages. If you’ve written a personal R package, you might include your miscellaneous functions there, or write a separate small package specific to your project.
Now go to the page about version control.