It's easy to say the All Blacks should win every test against Wales. In terms of history and form, that is unequivocally the case.
However, what I know from playing Wales and the other Six Nations teams that haven't had much recent success against the All Blacks, is that it adds an edge. As an All Black, you're protecting and enhancing the jersey. When you have a three-test series, one off day can change the course of history.
There have been a few close ones recently, and one which immediately springs to mind is the second test between the All Blacks and Ireland in Christchurch in 2012 when Dan Carter's dropped goal won it for the home side.
The All Blacks will be aware that the Welsh have one major advantage over them and that is they have recently played a test against England. They have a settled team who know each other and mostly what it's like to play here.
They played very well at the 2011 World Cup in New Zealand and are well coached with world-class players, many of whom are Lions. There won't be a sense of the unknown. They have the ability to win a test, and we are already underestimating them.