Alignments have evolved through the years, changing with suspension types. A front wheel drive car will probably require a 4-wheel alignment and a rear wheel drive car may only require a 2-wheel alignment. Aligning a vehicle truly means setting the adjustments…camber, caster and/or toe to the factory required specifications so the vehicle will travel straight down the road.
In some cases, after the alignment is performed, the computer system has to be re-calibrated to ensure the vehicle drives correctly.
Anytime a new set of tires is installed it is a good idea to have an alignment performed.