I have just a flimsy NUC6CAYH at home running nethserver on a 1.75TB HDD with 8GB of RAM. I was very cautious about power consumption (have to pay the bill), while providing a reasonable amount of storage space. It is running within my home network behind my router. Thanks to my ISP I have a 200MBit/s up and 12MBit/s down link.
It hosts a nextcloud, an openvpn server and cups for my printer.
I offer nextcloud space+calendar+address book to all of my friends and family to free them from the grips of Google (aka the "data kraken"). I also want to use it as a home theater, for which purpose I will install a graphical interface later on (yes, I know the words graphical and server should not be used in the same sentence. Please forgive me.)
The vpn is for being safe on the road in those unsecured wifi networks.
We have several devices in the house which I want to print from, but I only have a USB connected printer. So setting up this print server is the obvious choice.
For the backup I bought a Synology disk station which I will set up at my inlaws house. It will connect via vpn into the network. The idea is a logically, technologically and geographically redundant backup system (ligntning strike, fire or flood would take out all systems if located here). It's not finished, yet.