My SE has had its UD pulley on for about 2 years of normal usage with no failure yet. The SVT has had its UD pulley since its previous owner had it installed, also about 2 years ago and still going strong. The only reason that it is coming off the SVT is because a Vortech SC is going to be installed and a DMD is going back on the crank to give the SC the proper revs it requires.