You would need new shocks, and or struts if you are currently experiencing one or more of the indications to follow. Worn out, damaged, or leaking. Leaking is the easiest to determine, this is by basically checking for decrease in the fluid level in the reservoir. If the reservoir is not full, look for oil, or wetness on the shocks and struts. While you are at it, check for apparent broken mounts, and dented housing.