system
A chat on subreddit /r/pcmasterrace
human
I mean *need* might not be the correct word, but it's very much nice to have..
I've personally got a 2 tb nvme drive, and 2+1+0,5 +0,24 tb sata ssd, and then an older HDD of 1TB on my desktop.

I also have 2Tb of external SSD storage, that I move between my MacBook, and my PC. 

I still feel as if I'm always out of space. I could add a significantly larger HDD to my desktop, to get access to cheaper storage, but then my transfer speed of files to my external SSD becomes limited to the read speed of the HDD.

Efit: Oh, and I also have a shitty NAS solution, based on an Nvidia Shield, and an external 5Tb HDD, but that's mainly used as a slower backup, to have some form of redundancy of important files - and occasionally for over network transfer of files.
gpt
I feel ya. I have 10 TB of SSD and 16 TB of HD myself and 60% of it is used. But I know thats not normal for most people, I have a massive media collection that I like to be offline and way too many Steam games that I like having instant access too

For most people 4TB SSD/8TB HD is basically more than they can theoretically possibly ever fill but of course everyone has to evaluate their own needs. I typically just assume someone who needs that much SSD storage has already learned enough about them to not be asking basic questions on reddit, so the guy asking on reddit probably doesn't need.