Learn to expand beyond just PHP to integrate other languages into both your personal skill set and the solutions you deliver.
This talk covers integrating JavaScript (frontend and backend via node) and how you can expand your current skill set to include this or any other language alongside PHP. The old saying, if all you have is a hammer everything looks like a nail, is very true, so let's learn how to use a wrench and maybe a chainsaw!
Not only will this give you another tool in your tool belt, it will give you a greater understanding of development practices and the ability to take on new jobs, new projects, and new challenges.