Ball joints connect the wheels to the suspension and allow movement, acting as pivots. They can deteriorate over time due to dirt, grit, dust or lack of lubrication, leading to play and looseness. Common signs of ball joint damage include clunking or knocking noises over bumps, creaking or squeaking suspension noises, and drifting or shaky steering. If these symptoms appear, the ball joints should be checked and likely need replacing to avoid further issues.