I second the motion. I replaced to greens at least a decade ago. So far I have years of autocrossing, two track days as well as tens of thousands of miles of spirited driving - no failure yet.
A friend's car I installed a Wilwood disc brake kit on (which required snap-ring green bearings) is currently on its 4th set of bearings in under 2 years. The previous set (the 3rd) survived road use and drag racing easily. But rally and spirited driving killed it in ONE DAY.
My car did the same with tapered bearings (no rear discs), and they're still fine. They're at least 15 years old.
