Rotation has nothing to do with a brake job other than being convenient as the wheels are already off. I rotate every other oil change. Most people rotate 7,500 miles (plus or minus a bit). Many tire shops such as Sams Club or Costco include lifetime tire balancing and rotating. So the answer to your question is: Rotate if it is near the mileage to rotate. If you are using Radials, which is about 95% of all the tires made, then rotate front to back and back to front. Diagonal rotating is not recommended as it will often cause a pull left or right.