While pfSense will run on pretty much any hardware that will run the underlying operating system (FreeBSD), allowing you the opportunity to re-purpose old hardware, the process of hardware sizing and selection is still a useful exercise, especially if you embark on a career in Information Technology (IT), where the ability to choose the optimal hardware setup can be a valuable skill. If so, and even if you only have a passing interest in hardware sizing and selection, you may want to review this chapter before installing and configuring pfSense. A short-term investment in learning the fundamentals of hardware sizing and selection can yield long-term savings on equipment.