With the car at normal ride height. Can be a bit difficult to do but sometimes the inners will feel tight when the car is on the hoist and the suspension is unloaded. Then you put it on the ground and the inners are loose. I usually just disconnect the outer tie rod ends and check the inners for wear. It doesn't take much play for the rear end to feel very unstable. They are also pretty cheap on Rockauto or such.