320 =Common size in late '00s. Same with 250.
500 in the 2010s.
(For HDDs)
500 GB seems to be standard in the 2020s. It doesn't even look like you can get less than 500 GB for Western Digital HDDs now.
This reminds me of time I bought my first new storage drives! They were a pair of 320 GB Western Digital drives, back when they were still called "Caviar SE16". I want to say that was around late 2006 to late 2007. I was always using whatever 10 GB, 20 GB, or 40 GB HDD that came with the OEM PCs I had from the early to mid 2000s, so these 320 GB drives, and a pair of them at that, were absolutely massive to me (but far from the largest on the market). I to notice the "sweet spot" on price/capacity traditionally seemed to be whatever was around $100 (or a bit over), so I tended to buy there from that point forward.
A year or two later, 640 GB drives were now around there so I got a pair of those as well. They were still "Caviar SE16" drives. Not long later, I got another pair of 640 GB drives (and gave the original 320 GB drives to family PCs), but now they were called "Blue". I'm having trouble finding it, but if anyone remembers the exact timeframe that Western Digital introduced the color nomenclature and discontinued the Caviar naming, it would have been then, but I know it was the late 2000s.
I used those four 640 GB as combined storage until around late 2020 to early 2021. I moved to my first SSD, a 256 GB SATA, in late 2012, I added a larger 5 TB HDD in 2017, and the original SSD was replaced in 2020-ish with a 1TB SATA (and then it got replaced by a pair of 2 TB NVMe a while back when Western Digital ran that "buy two and get them $120 each" deal). I finally consolidated the increasingly-out-of-place four 640 GB drives with a pair of 4 TB (and then those quickly got replaced with 8 TB a year or two back). One is storage, with the other being (now external) backup.
Uh, there's my storage history to supplement my original post in this thread, haha.
My next hope is to get rid of the 5 TB HDD (this would get me down to just the one 8 TB internal, and I can live with a single storage HDD for the foreseeable future). I think I just need 8 TB SATA drives to get far more reasonable... so probably a ways off still.
And wow, after seeing some of the above posts, I feel a little less bad about the few HDDs/SSDs I have sitting around doing nothing.
Right now, I think HDDs below 4 TB don't even justify themselves, and I'd say that's moving towards 8 TB. I'm not saying
using drives below that size isn't justified, but on the current buying market, I don't think it's all that worth buying sub-4TB HDDs because below those capacities, SSDs are just cheap. I'm sort of surprised 1 TB and 2 TB HDDs still exist really, but there's always going to be an ultra low budget part of the market and home consumers' space needs aren't growing as much anymore, so... I guess that's why they stuck around. It's just weird seeing the capacity range from 1 TB (or less?) to 20 TB+, it's such a wide range now. Above 8 TB is where you're forced into the NAS or enterprise drives and those quickly get more expensive. The price gap between the 8 TB Blue and the 12 TB Red makes me cry. That's 50% more space but it's another $110 on top of a $130 drive. Not far off from doubling. Usually the value always goes up when you spend more on HDDs. What gives?
I hope there's HDD advancement yet to come still because it's seemed like it's been slowing, and I hope multi-TB drives become much, much cheaper in the coming years. That's sort of why I was hoping SSDs wouldn't go back up in price because we need larger capacities of those to force HDD prices down too.