Three things that indicate your car needs an alignment
1/Vehicle pulls to one side or the other if you are lightly hold the steering wheel, when driving straight ahead.
2/If you are driving in a straight line and the steering wheel appears to be off center.
3/The tires are not wearing evenly across. Take a penny, place it in the center and both edges of the tread with the top of Abe's head toward the tread. It should be the same depth all the way across. We use a tire depth gage that indicates 32nds of an inch. 2/32nds (or the top of Abe's head) means replace tire.
The Hunter alignment machine that we use allows us to check the alignment in the amount of time it would take to drink a cup of coffee. We love it!!!
If you would like to see it in action, click on the link below