Subnetting an IPv6 number isn't difficult. The theory, in so far as the pre-fix length denotes how much of the address "must match" is not a difficult concept. Other than that, it's easy enough, loooooooong numbers notwithstanding...
As far as being prepared for IPv6, if you know the basics (how to abbreviate them, how to identify them, and how they are constructed) unless you actually work on an edge device for an ISP or large corporate or multinational, there's no imperative to "be prepared". There's no compulsion, nor deadlines from any of the organising bodies to say that we must all switch to IPv6 by a certain date. We are free to use IPv4 on our internal networks for as long as we want. At least, that's what I understand to be the case. What we could do with is all those people/companies etc who are sitting on large blocks of IPv4 ddresses to release them back in to the wild
Of course, IPv6 brings some advantages with it that makes it an attractive option if you have a *large* internal network, but other than that, I can't see that the performance gain internally for small to medium sized networks would be worth the pain. Large companies with big routing tables that span many routers both across WAN's and across the internet may benefit, but even then, the migration is potentially costly and painful, especially as the ISP is probably routing with IPv6 already, and may well be looking after a dual stack edge device (or devices) for you anyway :wink:
. I'm just trying to show different opinions here so that we get a wider picture.