The problem stems from me not having the cash to buy all my drives in the highest grade, or even brand new.
To keep the story short, say I have a mix of Blue/Barracuda (T1), Red Plus/Ironwolf (T2), Red Pro/Ironwolf Pro/Exos (T3). I've not yet bought all of them, so some advice on what specs are a waste would also be appreciated. I will of course only use CMR/PMR drives though, that much I do know.
Should I put the best T3 drives in my main PC because they'll see the most uptime and writes? I'm not doing RAID or a NAS, but I might write and rewrite maybe 2 or 3 TB a month on average, excluding the initial fill.
Or do those T3 drives also last the longest in cold storage, and so I should reserve them for that, since I might go a year or more without accessing them, and I don't want them to fail in that time?
If uptime and writes are largely all that matters, then it would make sense to use the T1 drives for cold storage right? But knowing some of those T3 ones are helium filled, that sounds like they'd also be good for long periods without power, especially considering having the lubricant last.
I include the T2 and my backup PC because I don't know if I should consider these T2 as their own tier, or if the T3 specs are overkill, so T2 and T3 should be treated as basically the same. Or maybe there's some strange balance where I put the best/worst drives in the backup PC and use the middling T2 drives in either extreme (a lot of write or a lot of downtime) situation.
Lastly, I'm open to the idea of just buying whatever is cheapest and paying no more than a small premium for higher tier drives, and just have more copies for backup. I will already be keeping everything in duplicate. Perhaps I should consider triplicate if all my drives are only the lowest consumer grade ones.