Thanks for the replies so far. To clarify, the Mini 8's are probably the worst at pop/retract failure. The Super 800's seem to get about 2 good years out of them then go on the fritz. They're all plenty easy to replace, but I would rather spend some more money and spend less time replacing heads I've already replaced that current year.
Install heights have been the culprit on 2 or 3 of the instances, I'll admit that. However, the majority of them are at similar heights to when they were installed with steady foot & wheel traffic across them. I think in a basic residential situation they'd be fine, but they are costing me too much time.