only since last summer maybe, but saying that I had no knock or play found in my originals that were 8 yrs and 50,000 miles, I was just doing them as I was there doing wishbones anyway.
id expect these to last longer at least as they were supprisingly big side by side.
im sure you can jack up ,wheel off and use a bar to pry the antiroll bar up n down to see if theres any play or rattle.