Most people probably never upgrade their machines at all. In my case I used the same PC from 2009 until about a month ago. Over its 16 year lifespan it saw 3 GPUs, the memory was doubled from 6GB to 12GB, a Wifi card was added (and then got flakey after about 7 years but was able to switch to Ethernet over coax with MoCa), and an SSD was added for hosting the OS and most apps (original HDD relegated to additional storage).

If you're planning for a 10-12 year lifespan I have this advice. CPUs have surprising longevity these days as most usages don't significantly tax them, go a little above mid range on core count and it should last. GPUs are a throwaway item, plan to replace them every 3-5 years to stay current. Storage can be something that's worth adding if you're planning for a long lifespan and depending on usage. Photos, video, and games use more storage than they used to but personal photos and videos largely live in the cloud now. RAM you might need to upgrade if you go midrange but might not if you aim higher than standard in the initial build. The buses and interfaces become the main limiting factors to longevity. RAM technology will advance, PCIe and USB will have new versions. There may be new standards you can't take advantage of, like I was still on SATA II when the world had since moved on to SATA III and then NVMe.

Sometimes it's more about repairability than upgradability. My stuff lasted but I've had HDDs, PSUs, and fans die in the past. It's nice to be able to replace a dead part and move on.

I will also say that I'm a little surprised that the enthusiast market is still mostly these big ATX mid tower cases. They feel massive and unnecessary today when 5.25" bays are obsolete and storage is not 3.5" HDDs but an m.2 chips that sit flush with the motherboard. The smaller form factors are still the exception. Is it all to support the biggest and baddest high end GPUs that cost more than the rest of the system?

> Is it all to support the biggest and baddest high end GPUs that cost more than the rest of the system?

I think it's more to have a big window with lots of RGB LEDs to show off on the internet.

Newer SFF cases from Ncase/Formd/Louqe are designed with perforations or mesh on every exterior surface to maximize air flow. They can support an air-cooled 5090 and an AIO or massive tower cooler for the CPU. Put a 1000W SFX PSU in there and I don't know if you'd really be wanting for anything spec-wise.

> Is it all to support the biggest and baddest high end GPUs that cost more than the rest of the system?

For me, no. I bought a big case, Fractal North XL. It sits on the floor next to my desk so the size really doesn't matter at all to me, except I want it tall enough so that it's convenient to turn on.

It's a nice bonus that building and maintenance is also easier, but it's frankly it's the reaching convenience that matters the most. Could even be a bit larger still.