Our old family server was getting a bit long in the tooth, had a few random reboots and was running out of disk space anyway (plus it had an old 32-bit Atom CPU so that we could not even run Docker etc.). So in the end I broke down and ordered a new one. After a bit of searching around on the web I went with QuietPC.com and picked a much beefier machine this time than what we had before (back then I was going for size and very low engery consumption but in the end we paid for it with no upgradability and very slow speed). The machine arrived recently and looks fine. So far I am happy but it's too early to say much yet, I'll write up my experiences in a while.