Starting a new service and considering #ipv6? It's a good practice to go IPv6 for a number of reasons:1) IPv4 is exhausted, 2) IPv6 offers much better privacy thanks to the client address rotation, 3) IPv6 greatly simplifies P2P, 4) slightly better performance & latency
I'm also not convinced it gives better performance or latency, given that everywhere I have IPv6 it's going via tunnels.
My IPv6 address today is
2a02:390:79ef:0:bc7c:b971:4e32:1c20
Most detailed information you will get from WHOIS is 2a02:390:7000::/36 registered to my ISP somewhere in UK. And tomorrow the IP will be different.
This is not a feature of IPv6, it's how they've chosen to manage addressing, which could be applied to any addressing scheme.
A recent-ish paper showed that even /48 aggregation can still uniquely identify a single customer.
https://arxiv.org/pdf/1707.03900.pdf
If you're using your computer at work, you were probably getting more privacy from IPv4 NAT aggregation than you are from IPv6 address rotation, most enterprises will have fixed addressing to make network management easier.
Regarding stable IPv6 addresses - they are pain to configure as you have to use DHCPv6 and DHCP simply makes little sense with SLAAC. I've spent significant amount of time configuring DHCPv6 only to be able to track traffic in my LAN as all my personal and kids devices had different IPv6 addr each time :)
At the end of the day, I'm just tracking their MAC addresses as these are stable and configured everything else to use privacy extensions.
