I almost NEVER have my vehicles aligned and tires wear perfectly. If the alignment is on, it's on, and you would have to hit something pretty hard to knock it out, you pretty much have to bend something that holds the alignment in place. My daughter hit a curb so hard it blew out the tire and destroyed the wheel, but the alignment was still fine, no bent parts or other damage. Alignments are so over sold. If you constantly have alignment problems then it's likely the shop or mechanic not knowing what they are doing, it's not the car (there are a few exceptions). To me, it seems the shops with the latest and best equipment do the worst jobs, and shops with the old stuff know what they are doing...at least around here. Tire shops are notoriously bad at doing alignments.