My O-ring lasted over 150 flights. That is on a P60. And then someone pointed out the fact that if you align the turbine so that the plastic brackets holding the starter are at the 12 and 6 O’clock position then the starter doesn’t droop. I never saw that in the instructions, but after they told me it made a lot of sense. When it is installed the other way the weight of the starter does draw the plastic brackets a little out of alignment.