Something happens on almost every ride and it's a rare day I don't come home bleeding somewhere (though usually just a scratch from a thorny bush). So cuts and bruises on me are common and damage to the bike, scuffed grips, pedals and saddles, slighlty less common, maybe every 5th ride. I'll crack a helmet every year or so, rip gloves to pieces, shorts to shreds. Twist rims, ding the frame. All in the name of fun and still a lot less painful than playing rugby. But this is mountain biking, not roadie stuff.
On the road it's been a few years since my last serious crash (snapped chain major road rash) and I ran into the back of van that pulled out in front of me last year, no damage to bike, bruise to shoulder, statisfying dent in van door. Had a entanglement of riders during a training ride which led to some harsh words and bent spokes. I'd say something serious happens every 2 years or so (which means I'm due this year) and nothing else, no minor stuff on the road.