When it was time to upgrade the storage on my PC, I replaced both of my 1TB SSDs, bought a new 2TB SSD and 4TB HDD, and called it a day. I didn't think I would be thinking about buying more storage so soon, but here we are. I've realized I've delayed building a NAS for far too long, and I can't keep paying for cloud storage anymore. I need to take back ownership of my data, create a streaming server, and better organize my backups. And I need old-fashioned hard drives, not SSDs, for this project.
I have all the SSD storage I need
My main rig doesn't need more flash storage

A single 2TB SSD might seem insufficient to most users, but it's more than enough for my main gaming PC. I still have around 500GB free on the drive, and I haven't even deleted old games that I will never play again. A big chunk of my old photos and media collection is on my old external hard drive, which also stores my regular system images at the moment. So, my SSD isn't getting filled up anytime soon.
Even when I move to AM5 next year or so, I won't buy any new SSDs. I don't feel left out if I'm not running a cutting-edge Gen5 SSD, so there's no danger of splurging on one simply because my new motherboard will have a PCIe 5.0 slot. Any new storage that I buy will be the old-fashioned kind — hard drives for my latest project. Speaking of which, let's discuss that in a bit more detail.

Related
3 reasons that SSD speeds don't matter anymore
You might think you need the fastest SSDs on the market, but you probably don't
I want to build a NAS (finally)
Can't put it off anymore
Building a NAS has been on my radar for years, but I've been procrastinating due to the friction that such a project entails. I'll need to repurpose my old PC or buy a pre-built NAS, get some NAS hard drives, and set up the OS and other self-hosted services. This sounds like a lot of work to my convenience-addicted brain. Google Photos works seamlessly for my partner and me, and streaming movies from my PC to the TV is fairly simple, if not the most efficient.
However, I can't deny that I've paid hundreds in Google One costs that I can instantly eliminate by building a NAS at home. I'll also be able to run an always-on Plex server, and not have to rely on my PC running the entire 2 or 3 hours. I can even use it to store automated backups that I currently store on my external drive. So, buying a couple of NAS drives is suddenly on the cards now. I know I'm looking at around $350 for three 4TB drives, plus the effort to repurpose my old PC, but it's a one-time cost that'll pay dividends for years to come.

Related
Pre-built NAS vs. DIY storage server: Which one’s better for you?
Having a hard time deciding whether you should assemble a NAS or buy a pre-built enclosure? We're here to help out!
Hard drives are cheap and reliable
SSDs still can't compete here
SSDs might come out on top in terms of speed and convenience, but when you need high-capacity, reliable storage, hard drives are still the best. Of course, I can make a DIY NAS with SSDs, but that doesn't make sense from a financial or functional standpoint. The price per TB for 4TB or larger hard drives is far more attractive than that of even Gen4 SSDs. Plus, if I'm investing in a NAS, I'd want to make full use of it, which means tons of write-heavy operations — SSDs aren't really ideal in such a setup.
Hard drives, especially NAS drives, are built for relentless long-term usage, and they will not fail without warning. They also don't have a finite number of writes in the way SSDs do, so degradation over time is less of a concern. What all of this means is that even if I want to make an SSD-only NAS, the rational part of my mind will not allow it. Hence, my next storage upgrade will not be an SSD; it will be a couple of WD Red or Seagate IronWolf drives.

Western Digital's Red Pro drives come with faster motors, utilize more reliable storage technology, and up to 24 can be installed inside a single NAS enclosure.

Related
6 reasons I'm buying HDDs, not SSDs
I need terabytes on terabytes, which has a terrible cost.
Hard drives are cool again, I guess
I used to scoff at hard drives after moving to an SSD for the first time. After all, they were dinosaurs in the time of snappy flash storage. However, what I've realized is that I prefer HDDs to SSDs in many situations, and not just for my upcoming NAS. It acts as cheap secondary storage on my main PC and serves as reliable cold storage. SSDs might have made HDDs obsolete as primary storage on desktop PCs, but there are far too many use cases where they aren't getting replaced anytime soon.