I was switching the summer tires to gislaveds this past weekend and thought, while I had the wheels off, to take a look at the control arms (with ball joints) and sway bar end links (as some may recall, I've been planning to replace them). The thing is, I tugged and pulled and poked and generally inspected these parts and they didn't seem loose or worn in any sense... the rubber still looked rather pliable and the bushings all seemed to be in their correct positions. So my question is, how can I tell if these parts need to be replaced? Besides trying to diagnose them with driving techniques (which can be a riddle, I'm discovering) I was at a loss after my inspection.

Have any of you had experiences where they "look" okay but are bad, regardless?

Thanks!