Tires are rotated to even our tread wear. We rotate the tires so that all the tires do some duties on the front as well as getting a bit of rest on the back of the car. Most of the tires move from front to back, but patterns can vary on different vehicles.
Wheel balancing is required when there are some heavy spots on the tires that can create unbalance problems. Unbalanced wheels bounce as you drive along the road and can cause annoying vibrations at higher speeds, and also cause your tires to wear out prematurely. So a simple tire rotation and wheel balancing can help save you from more costly repairs or purchases down the line.