Discuss: Has anyone here built their own home server or home lab?

Overall, I've been far more satisfied building stuff like this myself than getting pre-built systems, because it lets me pick out exactly what I need, and also means that I know enough about the hardware to be able to repair or upgrade any given component without fear of things breaking.

Things to specifically look for:

• Make sure you get a MB that supports actually booting if there's no monitor and keyboard connected. Without this, you can't run the system headless, and you'll have to jump through hoops to get it to boot when attached to (most) KVM switches. Refusing to POST without having an attached display is marketed as a 'feature' for DIY PC builders (the idea being that if the GPU is bad, dead, or missing, you don't have to risk damaging data on the disk by cutting power). The keyboard thing is just a holdover from old systems that only supported PS/2 keyboards (which can't technically be hot-plugged). This is mostly an issue with older hardware, but some new boards still behave this way (for example, MSI still does this a lot).
• Avoid Gigabyte MB's if you plan to do anything with UEFI. I'm not sure about their more recent products, but a few years back they had what was generally considered some of the most user-hostile EFI firmware of any DIY MB brand in existence (wouldn't let you select between legacy and UEFI boot, would ignore boot configuration if it saw an MS bootloader on the ESP, had numerous other issues).
• Avoid OCZ SSD's. Many models had serious data retention issues (like randomly lose all of your data when powered off level of serious) due to poor decisions the designers made in the firmware.
• If you're getting old hardware, make a point to clean off any heat sinks and fans as thoroughly as possible, you'll get much better life out of it by doing so.
• Also make a point to replace any old hard drives or SSD's if you plan to use the system for more than just experimentation. These will usually be some of the most likely parts in an old system to fail other than fans (which are often more time consuming to properly replace, if you can replace them at all).

Check out reddit.com/r/homelab/ if you haven't already.

I've only gone as far as setting up a Raspberry Pi as a DNS server, running a Debian install on an old MacBook to use as a web server and setting up a Synology NAS.

Very much worth it. Before making the jump to LinkedIn I maintained a CCIE lab an F5 environment and a full on vmware vsan lab. I used old dell hardware