You’re not wrong, but I have been running complicated multi-site VPNs with a small homelab multi-subnet / VLAN setup for 25 years and still have yet to have a collision.

My home network is dual-stack these days, but because my IPv6 prefix is dynamically delegated by my ISP, I actually use site-private IPv6 addresses for all my internal servers and infrastructure.

The thing is though, I don’t even need IPv6. Comcast Business broke my delegation for six+ months and I literally didn’t even notice.

IPv6 tried to do way too much. The second system syndrome was strong. It’s no wonder folks are annoyed at the complexity, and as long as IPv4 continues to works for them, they aren’t particularly pressed to adopt it.

> never at a random 192.168.x.x in a network I happen to be connected to.

That’s a pretty good benefit, I hadn’t considered that!

Eh, I've been thus far unimpressed.

Part of it being that a lot of ISP's don't have static prefixes, they do get rotated pretty often and have no guarantee of CIDR size that you're going to get. By default my ISP will only give a single /64. You have to go out of your way to request more subnets and there's no guarantee that the ISP will honor that request.

It's really problematic to try and base a non trivial network setup, when you have no guarantee of how many subnets you can run. Today I've got 256. Tomorrow it might be 16. Or 2. Maybe just 1 again. ISP's can be weird when they smell monetization dollars in the water.

So I have to run a ULA in parallel to the publicly accessible networks specifically for internal routing, and then use a DNS server to try and correct it. Which works great! ...except when you run into this little niche operating system called Android. Which by default doesn't obey a network provided DNS server if you've got privacy DNS enabled. So if I've got guests over and I want them on a network in my place to access some sort of internal resource, then I've got to walk them through disabling privacy DNS.

Either that or I need to go out and buy a domain... for my internal network...and then get a TLS certification for my private internal domain.

I get how IPv6 can be great. But a lot of the advantages are also overhead I don't want to deal with.

Short hand is a good example; I've lost count at the number of times I've typo'd short hand addresses because my eyes skip over a colon. At this point I've gotten into the habit of just writing out the whole address, leading 0's included because the time saved from not making a mistake reading the address often faster overall then making mistakes with shorthand.