Check shock absorbers (dampers) by pushing down hard on the bodywork at the corners and letting go. The car should rebound once just past the level position, then go back i.e. one and a half swings.
Any more than this indicates the shock absorbers need replacing.
Listen for knocks from the suspension over poor road surfaces which could indicate worn bushes, joint and dampers. Take a note of the car's handling, if it is vague, "floaty" or bouncy, suspect worn dampers.
Check for fluid leakage from the dampers or struts. Slight weeping is acceptable - any more is not.