I'd just like to point out I'm not complaining, I was just hoping to get some insight in to why they've advertised such a long change window, I understand they have to leave enough room to apply it, and do some sanity testing before going live, and still have enough time to back it out if necessary ( if that's even possible). Personally I think the major time consumer is going to be the update, reorganisation and validation of the cosmetics database.
A big thank you to all who posted constructively.