I’ve got a box I made with a air filter and 200mm fan on one end, then it blows through a “tunnel” that has a network switch and 4 Raspberry Pis inside, one runs Frigate with an AI hat, another runs home assistant, another is running my Pi Hole, another is basically a NAS with a 2TB external USB drive, and they do a whole bunch of other miscellaneous ad-hoc tasks. The clean airflow keeps them cool just sitting there with open PCBs and the normal little heat sinks, they’re all wired to the switch so only 1 ethernet cable comes out.

On the one hand, a single Core i3 PC could probably handle ALL the tasks easily enough, but… what about when Frigate goes weird? I don’t want my whole home DNS/DHCP and home automation to go with it. Same for everything else, and if one of the microSD cards goes bad (none have yet after over 1000 days of 24 hour continuous operation except during power outages) - that’s just one thing going bad, not EVERYTHING.

I must admit the 2TB external drive is cheap junk, and those things do “wear out” - even internal SSDs go bad over time, I’ve had it happen at work more than once within about 5 years of normal use. I try to get the better microSD cards for the Pis and so far they’re not having problems for me.

One thing you can look into if you like messing around with system configurations is partitioning your microSD with “immutable” partitions where any changes are written in RAM (yes, RAM heavy Pis are even more expensive than they used to be, but it all depends on your application…) I do this for my Pis that run around in the world and get their power cut off without warning - failures are so rare in the first place it’s hard to know if all the partition work is worth the effort, but so far I’ve never had a corrupt file system with the immutable partitions carefully configured, and I have had several before I started doing that - not failed SD cards, just corrupt filesystems that needed to be re-formatted.