The tension force of a spring is considered conservative because it can store and recover energy when deformed. In contrast, the tension force of a rope is not inherently conservative, as it depends on the rope's material properties. Stretchy or springy ropes can recover energy, making their tension conservative under certain conditions. However, ropes generally do not allow for energy recovery when pushed or deformed in a non-recoverable manner. Thus, the classification of tension forces as conservative or non-conservative hinges on the rope's ability to return to its original state after deformation.