I use old laptops as my primary home server instead of mini PCs because they come with a built-in multi-hour UPS and a crash cart.
Using old phones offers similar advantages, in particular if your alternative was a Raspberry Pi.
https://hackaday.com/2025/08/16/from-smartphone-to-a-home-server/
I use a rack that was originally designed to hold the lids from cooking-pots as a way to keep my laptop collection vertical on my desk. It reduces the footprint on my desk and allows for airflow around them (and unfortunately dust getting on all of them, too 😆) Mine is slightly sturdier than the one in this image.
Kyle Rankin
Tim Chase