My car only had around 155k on it when I replaced the shocks (which looked original). They were absolutely shot - you could move them up and down with your two hands, there was little to no pressure, and they didn't bounce back to their original position. And no, the weren't leaking, so I don't buy the argument that you should only change them if they leak. I had the exact same situation with struts in another car I once owned.
Change in handling of the car was worth every penny spent. On the other hand, if your tires are wearing o.k. and you are satisfied with the way your car handles, the leave well enough alone.