About a year ago, my mechanic points out to me that one of the rear tires has worn badly on the inside, so much that the steel belt is visible. I could have replaced 2 but since there wasn't that much tread on the fronts, I did all 4. The tire place was offering a 3 year alignment package for not much more than the one-time alignment clearly needed, and usually I pass on this, but this time I bought it. Took the X5 back last August and it needed some minor adjustments. I'm due to bring it back in again. Not sure if it's my wife's driving style, or the speed bumps she slams going to/from home. In either case, I feel good about buying the package (3 years, every 6 months) for less than $200.