It very much depends on how much refinement bonus your character has. Sources of refinement bonus can come from following: Band Attributes bonus Character Mastery bonus Decos (costumes) bonus Epithets bonus Tender Stones bonus New Premium bonus Special Event bonus With sufficient bonus, you can refine weapons and clothes pretty safely up to a certain refinement level without failure or breakage. Refinement of clothes may fail and break from +5 onwards. +1 to +4 is safe from breakage according to a previous game announcement. Unfortunately I am unable to locate the source link at the current time.
