Yet outside half Carter, one of only a handful of players to start all four games of the trip, believes the strength of the All Blacks squad will ensure a rousing finish.
Carter said, "I'm feeling fine and the body is still in good nick, though I've been taking things easy this week so that I'm totally ready come Saturday. It's been an extremely long season for all of us but I think the coaches have managed the players really well and I don't think fatigue will be an issue in this game. There are only three or four players who are playing their fourth match of the tour this weekend and that's because of the strength in depth we now have."
New Zealand coach Graham Henry has made seven changes, including one positional switch, to the team which beat France 23-11 in Paris ahead of the clash with Wales.
Carter, this week pipped to International Rugby Players' Association Player of the Year award by teammate Richie McCaw, reckons that rotation policy will pay off in the long run.
He said, "A big issue for us is guarding against complacency and the competition within the squad does that. No one is totally sure of their spot in the team and that keeps all the guys on their toes. Everyone is trying hard to be selected and are then pushed to be the best they can by the rest of the guys if they are picked.
"Our performances have attracted attention but we always aim to live up to the standards we set ourselves."
This weekend they face a Wales side unbeaten during the Autumn series following a draw against Australia (29-29) and comfortable victories over the Pacific Islanders (38-20) and Canada (61-26) this month.
Wales have been strengthened by the return of Carter's opposite number, British Lions No.10 Stephen Jones, and have named Kiwi-born Sonny Parker ahead of star centre Gavin Henson.
Carter said: "It's a big plus for Wales to have a great player like Stephen Jones back. He's been around for a while now and he uses that experience to read the game but he's also a big motivator for them. Sonny Parker played very well over the last few weeks; he's an extremely strong and powerful player who is very solid in both defence and attack.
"We've been impressed with the way Wales have been playing in their recent games, they're playing with confidence after the last three games and are prepared to throw the ball around. They've got dangerous players who capable of breaking any defence so we will have to be on our toes.
"I always love playing here in Wales, there's always a great atmosphere at the Millennium Stadium and this is going to be a tough match."