I could go into details as to what a homelab is, why have one, what does one do with a homelab, but the homelab subreddit over on Reddit has done a pretty good job of compiling these questions into a handy wiki post I’d suggest you take a look at if you are new to the concept of a homelab. I assume this page will be up for the foreseeable future, but just in case it goes somewhere I’ll summarize the more important part here.
Why have a homelab?
The answer is easy: to learn. IT professionals, amateurs, and people who just really like computers use homelabs to experiment in. It’s a sandbox environment where if you break it, you fix it, and more importantly it isn’t costing money while it’s down.
I’ve maintained some semblance of a homelab for at lest the past decade, only in the last few years operating with a more formal “production-like” setup.