This one replaces a machine that had several functions.
1) It was the utility machine down in the garage, so that if I was doing stuff there, I wouldn't have to run upstairs to use a computer.
2) It was the main internal nameserver. The IP addresses that I use internally, are all different from the ones that people external to me use to access the computers that I allow access to. So I need an internal-use-only nameserver to do the name-to-ip-address translation for computers inside my network.
3) It was a DHCP server. Ladysolly uses DHCP addresses for her various devices, and I use some too.
So I wanted to use DNSMASQ for the DHCP server, but I disabled it's DNS server abilities, because I'd rather use Bind, because I'm used to it's little ways. Also, it has to respond to two different IP addresses, so that computers that I prepare for taking up to Cheltenham, can be given the configuration that'll use when they are in place. That's so I don't have to reconfigure them at the last minute before taking them there.
Also - it uses a CRT monitor. There's not many of those being sold now, but I still have a few perfectly good ones in use. To use it with a Pi, I had to get the right parameters in /boot/config.txt
That gives me a decent resolution (I think it's 1280 by 1024, the documentation calls it 720p) and removes the blank space at top and bottom.
So it was a fairly complicated install, but I think it's OK now. The Pi is housed in a cardboard case, which was formerly the box that a SATA card came in. It's just about the right size for the Pi and will do the useful job of making sure that it doesn't touch anything metallic and thereby short.
This means that I now have eight Pies sitting in a drawer waiting for me to find a job for them. That's OK - I usually have several motherboards and CPUs sitting around for future requirements. It means that when something stops working, I can replace it immediately, without having to wait for replacement parts to arrive (or worse, finding out that the replacement that I need, is no longer available).