#31955, "RE: Terrible squeak coming from suspension..." In response to In response to 11
I'd replace both of them at the same time. What you will probably find out though is that you have more ball joints that are bad. It gets expensive replacing everything at once though. I've been down that road before. You could replace them one at a time if you don't have the cash to do everything.
You will need an alignment though once you start replacing worn components.