update-per-45-degree-sector.cs

int lastUpdateSector = 0;
void Update()
{
  xRotation = Mathf.Repeat(xRotation, 360.0f);
  int currentSector = (int) (xRotation / 45.0f);
  if (currentSector != lastUpdate)
  {
    int n = lastUpdateSector - currentSector;
    n = (n >= 0) ? n : -n;
    if (n > 4)
      n -= 4;
    for (int i = 0; i < n; ++i)
    {
      // do your stuff
    }
    
    if (n > 0)
    {
      lastUpdateSector = currentSector;
    }
  }
}