@james hear is how I feel repairing should be done.
Stone Age: wood and stone tools can not be repaired.
Industrial Age: copper, iron, gold, silver, titanium, step 1: place 1/3 metal used and your broken “metal” tool in the furnace the ore will be used up in the furnace and the tool will become red hot. Step 2: Take the tool out of the furnace and place your hot tool on an anvil were you will strike it with a blacksmiths hammer.
Step 3: Each strike of the hammer is an rng roll successfull hits fix 25% dura failed hits have a chance of putting a defect on your tool/weapon or reduce its durability by 25% after 4 hits the process will finish.
Tools can not be placed in the furnace unless they are broken. Success on the anvil will be based off of how many of that type of ore tools you repaired.
Example:
Fixed 100 iron tools success rate improves for iron tools
Fixed 100 titanium tools success rate improves for titanium
Ect. ect…
forged tools will require a binding catalyst poured on it before placing it in the furnace. If no catalyst is used then it will be destroyed in the furnace.
The catalyst will protect the tool while it’s being repaired. But a side affect will cause the forged too to be bound to the next person who uses it.
This method could be used for gem tools aswell or could use method below.
Tech age: gem tools will be repaired in a laser cutter requiring different levels of power to repair along with 1/3 raw gems to craft the rest is the same method as above 4 tries with laser cutter each missed hit can cause defect or 25% dura loss.
Forge gem tools will require the catalyst poured on them before you repair.