If the vehicle develops an annoying, clunking sound when driving over bumps it is usually the struts and strut bearing plates. These may need replacing at 100,000-125,000 miles or sooner. If the noise is a more of a squeak or groan, it can be usually be eliminated by spraying a light lubricant on the suspension bushings 1-2 times per year.
Car Problem Reports
Toyota Corolla Sound When Driving Over Bumps May be Struts/Bearing Plates
Toyota Corolla Problem
Average Mileage: 103,333 mi (55,000 mi - 175,000 mi)