For the 64bit suffix there are ipv6 privacy extensions. For the prefix some ISPs hand out a whole /56 to the user so their CPE can rotate through multiple /64s

For the 64bit suffix there are ipv6 privacy extensions. For the prefix some ISPs hand out a whole /56 to the user so their CPE can rotate through multiple /64s over time. And of course just like they can shuffle IPv4s they can also shuffle IPv6s.