Most drivers are unaware of the fact that each strut or shock goes up and down about 1,750 times every mile at average highway speeds.

Under this kind of a workout, this adds up to 15 million times for every 25,000 miles of highway driving.It is therefore important, points out Mike Holdaway, president of AAA Springs, for drivers to have their suspension checked.

When the suspension is in good working order, then so is handling. And when it's not, then handling suffers.

The average driver may become used to less than optimum handling and stopping ability on bumpy roads. In an emergency, however, that may not be the case.

Suspension wears out, he notes. Drivers may notice it when the car starts to sag, or the ride is bouncier than it should be, or unusual tire wear is noticed.

He recommended drivers have their suspension checked ever 20,000 miles for a car or 12,000 for a truck.

"It's something drivers sometimes overlook until it is too late," he said.