Proper wheel alignment is very important to the way a vehicle handles, tire life, as well as "rolling resistance" for fuel economy. At the factory, alignment is set with very sophisticated equipment. In the best of worlds that setting will last for the life of the vehicle. However, in the real world, alignment can be effected by all manner of road hazards. When alignment is off the vehicle can lead to one side, make a vehicle hard to stay in your lane, and drag the tires down the road. This is most importantly unsafe, hurts fuel economy and effects tire life. While aligning just the front of a vehicle (2 wheel) can help vastly. It is always better to align a vehicle with all 4 wheels set together (4 wheel). This makes sure all 4 are properly aligned to each other. We recommend an alignment every other year, whenever you are unsure of how the vehicle is handling or whenever the tires show signs of uneven wear.