I have Shimano XT 737 hubs with Rhyno Lite 700c rims, 36 spokes.
I had a broken spoke a few weeks ago, but upon taking it apart I found that it was caused by damage from the chain falling off the big cog onto the spokes. I was afraid the spokes were breaking from fatigue rather than acute damage. So far about 10000km (with much gravel road and loaded touring mixed in) on those wheels.