Here's my current drives.
I have another external drive that probably has statistics similar to the 8 TB drive here (it's the same drive and was purchased at the same time), just with less hours on it since I moved it out of the system and into an external enclosure a while back.
Not very high hours on most of them as these are all "newer" (relatively speaking, two or three years old at most) besides the 5 TB Black, which is from early 2017. Even my previous 4 TB drives probably aren't
that old (mid-2020) and weren't used all that much before I replaced them with 8 TB equivalents. I feel bad that they, and a 1 TB SATA SSD, is just sitting unused. If I were get out my pair of 640 GB drives from the late 2000s though, I think those might be pretty up there in hours, but I stopped using them a few years ago.
My oldest SSD from 2012 (Crucial MX100 256 GB SATA) is in use in another PC and I think it's down to around half of its estimated life remaining, but it still works just great.
I probably do have a higher lean towards writes than most people, so while I don't need instant, on demand access to my storage drives, this is a reason why I shy away from SMR drives.
I can only assume that I've lived a blessed life. In all these decades the only piece of major hardware that I have lost was a Corsair HX PSU and it was only 3 years old. I've kept PCs far longer than a normal lifespan I think. I had a Dell at work that I used daily for 10 years and nothing ever went wrong with the hardware. I was glad when the IT dept replaced it when they implemented Windows 10 though. But really it was still fine for what I needed if I had to keep it. MS Office and an inventory database and tracking program for 84 locations.
Definitely lucky!
While I share your luck when it comes to storage drives, I've seemingly made up for it by having poor luck with other things. And most of my poor luck has been in recent years as opposed to my earlier years.
That might by coincidence. I do, after all, not buy hardware often so my sample size is low enough to be skewed heavily by random chance. But I've come away with the impression that quality might be slipping in recent years. Motherboards and graphics cards (but also a PSU, and not due to the PSU itself but a fan) are where my luck seems to be bad.
I started out buying used hardware in my earlier years (especially graphics cards), but motherboards and graphics cards are probably the two things I wouldn't chance buying used anymore. At least, not for my main system where I'd need to spend a lot.
Drive starts and stops are the hardest thing on them, once a drive is spinning the only wearing os the bearings unless it's gets bumped hard enough to crash the heads.
I remember decades ago, like in 2000s, this was a point of discussion/debate on some forums. "Is it better to let them run all the time compared to starting and stopping", and it seemed like there was reasoning for both sides, but no hard data showing which was better. It was probably a "it depends" thing, and I recall it was generally "agreed upon", if you want to call it that, that it probably didn't matter in most cases. I also recall that the "starting and stopping is more wear and tear" was specifically true of older hard drives (like, from the 1990s and earlier) and was wisdom that persisted through the years, despite maybe not being as applicable as back then. That's not a statement that it's not true, mind you, but it was something I read.
What I can say is I let my drives start and stop and they've been fine. I have no need to have my hard drives spinning constantly as it's added vibration, noise, and heat, and I don't need "instant, on demand" access to them regularly. And if there's a slightly higher risk of failure that way, then so be it.
A 4T drive likely uses SMR (Shingled Magnetic Recording). The tracks are so close together, that rewriting a sector damages adjacent tracks. The controller deals with this by dividing the media into "zones" similar to flash media "erase blocks". Sectors are only appended to a zone, and starts over when full, and the controller manages mapping. All this can make even small writes take a long time. I would avoid >2T HDD except for backup media (and I still prefer 2T for that application).
Very much depends on model, not just capacity.
For "portable" drives (2.5" external ones). 1 TB and below is likely CMR. 2 TB and up (they come in 5 TB or now 6 TB as the highest capacity) are all SMR.
For internal drives, all drives above 8 TB should be CMR I think? Most 1 TB and below should also be CMR. At 2 TB to 8 TB is where it's "it could be either" and it depends a bit on brand and model. For example, the Barracudas between 2 TB and 8 TB are all SMR I think. For Western Digital, it's more of a mix. The Blue 4 TB has both a CMR (EZRZ) and SMR (EZAZ) variant. At 6 TB, it's only SMR (this explains situations where you may notice the 6 TB Blue drive is barely more expensive than some 4 TB Blue drives, because that's probably the 4 TB CMR model, as CMR is more expensive than SMR). At 8 TB, the Blue is only CMR, as the 8 TB Blue is effectively the same drive as the 8 TB Red but renamed with some feature differences if I'm not mistaken (this explains the odd 5,640 RPM instead of 5,400 RPM at the 8 TB capacity), whereas the Seagate Barracuda at 8 TB is only SMR. In other words... it depends.
Both Western Digital and Seagate have, thankfully, gotten better at disclosing this information on their websites after the mess it caused years ago, where I think a Black and even some Reds were SMR.
Though I bought late enough in the cycle to know that buying the 45GB version was safe because it used a different internal design so did not experience the higher failure rates of the 60 and 75GB versions. Neither of mine failed before being retired. The 1.5TB HDDs I had were also notorious for high failures, as shown by BackBlaze in one of their earliest press releases.