Start with the effect, not the label
Decide what the equipment needs to do. Unbreaking improves durability while Mending uses collected experience orbs to repair an item; they serve different purposes. Check whether an enchantment applies to the held item before spending resources or trying a command.
Read the complete cost
An anvil can combine compatible items or apply an enchanted book. Reworking the same item affects later costs, so inspect the displayed result and level requirement before confirming. Repairing and naming are separate choices; do not spend levels on an item you intend to replace immediately.
Use a test world for syntax
The command finder’s Unbreaking example is an administrator tool, not the normal Survival enchanting loop. Hold the intended item and use the syntax for Java or Bedrock. A valid command still has equipment-compatibility and level limits; it does not make every enchantment combination legal.