and the car tracks ok and the wheel is straight then there is no reason to have the car aligned.
My 02 Boxster out of the box, well, off the dealer lot, had what appeared to be a good alignment. Where I think it went wrong was when I had it in for a RMS replacement and the car was moved with the tranny removed and the stiffener panel removed and the alignment was affected. Had the car been left on the lift it would have been ok. Afterwards, tire life appeared to be unaffected but my checking of tire condition was cursory and I was not noting the inside edges of the rear tires were wearing until closer examination found the inside edges worn to the belt material.
Upon fitting new rear tires I had the car aligned and tire wear once again became even and tire life was very good.
Unless tire wear patterns indicate misalignment I do not have the car aligned unless as has been the case at least once or twice if the dealer offers a discount alignment coupled with a set of new tires, then I have the car aligned. In at least one case the alignment cost was $100 and another time I recall the SM gave it to me at no charge. (The last time though I had the 996 in for new tires and it was clear the car needed an alignment -- the result of nudging that sidewalk curb in a OK hotel parking lot late one night over a year ago -- the cost was $340.)
The one time tire wear patterns indicated an alignment problem was after I brushed a curb with the side of the right rear tire. Even though the tire sidewall received no real damage and the wheel was not even rashed that tire exhibted over time uneven wear. Sure enough upon alignment the toe was out on that side.
Now on the other side just a day or two after I bought my 08 Cayman S it was clear the alignment was not right.The steering wheel was not centered and there were other signs of alignment issues though nothing horrific. I took the car back to the dealer and asked the car be aligned and after some discussion it was and sure enough the alignment was off. Afterwards, the change was dramatic and for the better of course.
Same with the 996. After spending a few days driving the car around and getting used to it it was clear the alignment was not right. The car had new tires -- the original ones replaced due to age (the car was 6 years old wen I bought it with just 10K miles on it) -- so I took the car to Rector Porsche and had the car aligned. Afterwards, the car was transformed and like the Cayman for the better.