By design they will last a long time, I remember S&W testing alloy frames by running approx. 30,000 rounds through a 9mm without any major issues. At the same time each individual gun may be different based on possible manufacturing or materials defects, ammo used, how well or poorly the gun is treated, how often maintenance is performed (including spring changes), etc., etc. It would not surprise me to find a 3rd Gen that has pushed past the 50,000 round mark.