I swear it always seemed like if I used my horse to get a kill or more per round I wouldn't get repaired. But if I died early and didn't kill anyone when I was mounted, it would be more likely to be repaired.
Also, it seemed like if I stayed alive the whole round (and my team won) I'd be less likely to get repaired. I'm sure it's just correlation (or a coincidence) and not causation. But that's what it seems like to me when I'm playing.
Also, CSB time:
I'm on my first generation build as cavalry lancer, I had everything I wanted paid for and about 9k. I bought a long bardiche for when I'm on foot and brought me down to basically no money. So I ran around naked w/ my long bardiche for 4 maps and never got hit with a repair, made about 7k in those maps w/o being hit for repairs. Obviously the less equipment you have equipped, the less chance you have to get hit with repairs. Basically each item has a "roll" for repairs as far as I've been told. I always thought it was a chance per round, not a chance per tick, but either way it's not really anything you can control.