I haven't bought much off the AH for my team (they're 41 now) - I have always been more concerned about having gold for my mounts which I will be able to purchase tonight without having to use any of my other chars gold. I just use the items that drop from instances and some quest rewards. But I can see where better gear from the AH can make things a lot easier and I am expecting to get more gear in my later levels as I approach 60