I just recently replaced two of my tires because the alignment was off on my SVX. It was so bad that I chewed up two Bridgestone Potenza RE730's in less than 18,000 miles. One of them had gone completely bald all along the outer edge. I thought it was a wheel bearing because the worn tires were making a very similar noise. From now on I will check my tires every month and I plan on having the alignment done twice a year.