I just had mine replaced at over 180,000 miles. Not sure if it had ever been replaced before. (I doubt it had since it only had 103,000 when I purchased it.) The mechanic at the dealer recommended that I replace the tensioner while they had it apart to do the timing. They also replaced my accessory (serpentine) belt. I think for my car (99 S70) the timing belt is supposed to be changed at 105,000 miles. If I were you, I would go ahead and get the tensioner replaced while they have it apart. Better to be safe than to need a new engine!