Yeah I think the only reason this route over NAS is I already have a pc that’s sitting there doing nothing. I mean I could sell it but at this point my return wouldn’t be worth selling I don’t think. I’d rather keep it as a server for now and absolute back up if needed.
Mainly larger video security storage and long term files that are not needed to be on main pc.
The cost when you start going this route becomes mainly hard drives...but spinning hard drive prices per TB keep dropping.
If you are going to leave the PC on 24/7, you have to look at power draw. If it's an older PC, it will draw more power than it has to...a new modern NAS will draw less power. You can look at your electric rate and see what the pay back period is.
Either way, at least get 3 drives and do a RAID 5. In a RAID 5 array, 1 drive can fail and you still don't lose your data. (You have to then purchase a new drive and "rebuild" the array). The downside, is that you "lose" 1 drive worth of storage. (In other words, 3 x 4 TB of drives gives you 8 TB of storage, not 12 TB).
Personally, I run the following:
System 1:
--- Runs Plex server, a couple of VMs
--- 8 x 4 TB drives in RAID 6: Gives me 24 TB worth of storage, tolerates a 2 drive failure
------ Main bulk file storage
--- 4 x 5 TB drives in RAID 10: Gives me 10 TB worth of storage, can tolerate at least 1 drive failure
------ This is a "fast array" I use for "fast" stuff and not bulk storage
System 2:
--- This was my first NAS (System 1 is my second)
--- 4 x 8 TB drives in RAID 5: Gives me 24 TB worth of storage, tolerates 1 drive failure
------ this is the "backup" for the 8 x 4 TB array in system 1
Good luck - and feel free to ask any questions here. We have a lot of dedicated nerds/geeks in this community who practice what they preach!