There's an NPC in each town that will repair your gear up to 75% durability. Also, you can list your damaged gear in your bazaar for repairs. Make sure to offer a fair price or at least the crafting material needed. If you park yourself near a crafting hub someone will eventually repair your gear as it's free skillups for them if you offer the crafting material as a reward.
What I haven't found is an NPC to repair jewelry.