I've been fairly good on getting op-ups in the last few years. While I just purchase D1 tickets for 50-60% of my international segments, I have been op-upped for probably 25% of my international flights where I was originally in the economy cabin. Last summer my wife and I both were upgraded LHR-PDX while traveling on award tickets.

My best story around this was that I had a contract with a non-profit organization in South Korea a couple of years ago and I was op-upped on 5 of 6 SEA-ICN-SEA segments in an 8 week period. I booked all my flights in economy to help their budget but I guess that was good karma.