In patch 1.18 the current repair system will be replaced with a new, simpler system. The idea behind the change is to limit the amount of repair materials that players need to carry. Instead of using many different repair materials per crafting class there will be universal repair materials that all crafting classes use to repair. In total there are five different materials and which one used depends on the rank of the equipment being repaired. The post on the Lodestone is quoted below.

"Simplifying Repairs

Patch 1.18 will see all repair materials replaced with a universal item called dark matter. Dark matter comes in five grades, each of which can be used to repair equipment whose optimal rank falls within a certain range. As long as the range is correct, dark matter can be used to repair equipment of any class.


Grade 1 Dark Matter - Use to repair equipment for class ranks 1-10.
Grade 2 Dark Matter - Use to repair equipment for class ranks 11-20.
Grade 3 Dark Matter - Use to repair equipment for class ranks 21-30.
Grade 4 Dark Matter - Use to repair equipment for class ranks 31-40.
Grade 5 Dark Matter - Use to repair equipment for class ranks 41-50.

* Dark matter can be obtained from vendor NPCs, as guildleve rewards, and through gathering.

Repair System Adjustments

From patch 1.18 onwards, repairs will always be successful when made by those who possess sufficient rank in the appropriate skill. Furthermore, the chance of conducting repairs without expending materials will increase slightly overall.

NPC Repairs

In order to improve the usability of NPC repairs, the fee for such services will be greatly reduced."

Source: The Lodestone