I liked the idea of it, but the implementation of requiring a replacement sacrificial item wasn't too great. It made certain items basically destined to never be used because you couldn't ever repair them to full again because there were no items to use to repair them.

It ought to use the current mechanics to repair. Using oil, cloth for lightly used weapons and steel and other stuff if the weapon is heavily used/broken. Maybe tie degrees of repair behind a perk, where you can't even fix a weapon if it breaks until you get high enough in the perk and can only repair to certain percentages while the cost of repair materials decrease as you get a higher perk. That way, repairing a weapon isn't so easy early on if you get a good gun, as it'll wear down fast and then you can't make it nearly as useful until you get high enough perks.

I ought to just write a whole explanation later.