A pet or side project, in the sense that I am referring to it, is something you can work on that is related to UX and will, in some way, push you forward in your career. It may or may not actually benefit the organization you are working for, but is something you can ethically work on while on the job. In most instances, I try to ensure it is something I can call “professional development” if someone asks me what I am doing on any given day.
Some examples of pet projects I have worked on in the past: Ethics in Design (research), Alert Fatigue (research), Patient Timeline for an EHR (visual design concept), Representing Time in Interfaces (research and design), Setting up a UX Research Program and you get the idea.
Most of my side projects involve some level of research. But, you can have side projects that concentrate on conceptual designs or visual designs. Even reading a book about UX could be considered appropriate during working hours and professional development. I also have themes to my side projects. For example, I may spend years studying something like behavioral economics and applying it to design. This could have me researching many source and working the research into design concepts.
I don’t think redesigning FB or Twitter or any of those types of projects are useful (unless you work for one of those organizations). Some hiring managers will obviously disagree with me. But those types of projects are essentially free of constraints and direction. They aren’t real-world projects where you have requirements or stakeholders to satisfy. You are essentially designing for yourself with those projects and don’t have to contend with colleagues and stakeholders who will have input as to the direction of the design. That is all a big part of design.
Thanks for the read and for taking the time to engage, Fiel!