Hardware Hobbyists vs. Emulator Enthusiasts vs Replica Recreators

Warren Wolfe wrote: Glad you think so. So Tony, perhaps you could join in, in the same style and write up a bit of what you love about old hardware and keeping it running, what's enjoyable and rewarding about it, etc. Did anyone build a replica? If so, perhaps you could write a bit about what you enjoyed about that, and how you went about it, and we can put all the stuff together into a single article explaining the joys of our hobby? I'd guess it should be kept generic, not mentioning any specific system so as to attract readers to the hobby rather than to a specific machine or interest. So we have hardware work, emulator work, and replica work. Any other big field I've missed that can be part of this hobby of ours? Perhaps why we actually collect and how we go about obtaining machines, peripherals, data, and how we let others know not to throw out old machines, but to let us know about them first so they can be rescued?