They are a cheap way of engineering a smooth ride. I'll never forget how they acheived ride stability in early '70's Cadillac Eldorados. They mounted a latitudinal tube in the rear with a monorail track inside supporting a very heavy lead weight attached to spings at either end. As the car cornered the weight swung to the opposite flank effectively leveling the vehicle on the cheap. The springs re-centered it on the straights. Spring helpers are the same inexpensive way of full-time ironing out the vehicle vibrations and undulations. You should renew yours today and see the difference.