Interesting. My AOS never failed, 110k miles on a 98 car. I did have a smoke cloud once but it was the result of oil overfill by my trusty Porsche shop.
I misdiagnosed the problem and replaced the AOS but after cutting open the original one I found it was still in serviceable condition. Oil changes every 3000 miles and lots of track duty at various elevations. I live at 1500'. Castrol 5w40