Two theories here. At this point many will say don't bother now, and I would likely be one of them. If they have 30+ passes on them and you rotate them now they likely they will not be happy for a number passes if at all. The other camp will say rotate them on a regular basis, like every race or two at most. We do rotate ours every 15 passes or so on the dragster and did on the Cuda as well. On the heads up car we do it every three passes. We seem to get a lot of tire life on that car for what it is for sure. I know a lot of people who never rotate their tires as well. I am not sure there is any scientific data to support any of it being better or not, for years many slicks were one directional, so they could not be rotated. I also think it depends on the car, power level and rear suspension type, Ladder bar cars are inherently hard on tires, they have a lot of bite and most are not controlled well. That will kill the sidewall long before the tread is gone.