Tire Rotation: How often should we do this?

[MrQ]

I made sure when I got two new tires put on that I had them rotated with the "X" pattern. The deal is, is that the back wheels are static, no camber or toe. The front wheels are dynamic and change with the steering. In my specific case, the twin "I" beam front suspension on 1st gen explorers causes a greater wear on the inside of the tire. So, it is always good to use the "X" pattern to get the outer wear on the tire.