Wheel alignment is important to the health of your car or truck. If you hit a massive pothole, you might bump your suspension out of the carefully calculated locations that the components have been set. All of the elements that make your car go straight are called "alignment." Some shops try to make it seem like rocket science, but wheel alignment is a fairly straightforward affair. The inclusive term "wheel alignment" involves three main measurements -- caster, camber, and toe. These measurements have standards that a technician uses as targets of adjustment. In other words, get as close as you can to the right measurement.
The good news is that most modern cars only have adjustments for toe. Caster and camber went the way of the dodo thanks to the McPherson strut.