Currently, there's only one auto repair. As soon as one item is damage, it gets repair.
I'd appreciate to have other sorts of Auto-Repair :
Auto-Repair from beyond Normal : As soon as one item goes beneath Normal status, it gets repaired. (heirloomed stuff gets repaired only after the 2nd/3rd/4th break.)
Auto-Repair from Broken : As soon as one item reaches the Broken status (aka can't use anymore), it gets repaired. (don't care about lower stats, you just want to use the weapon, and try to gain more gold)
Repair cost is the same anyway, but this will allow more players to have their equipment auto-repaired without going back to the site, cause if you want to save some gold, at the moment, you have to switch off the Auto-Repair (on Settings) and do it manually.