Talk:Mastery Rank/@comment-75.87.131.158-20170209040052/@comment-25254386-20170209043717

"Each individual item (such as a weapon or Warframe) only grants its Mastery XP once per level. For instance: leveling an item to max level, selling it, then leveling it again will not result in additional Mastery. Releveling an item after Polarization results in the same situation.  However, if an item is sold before reaching maximum level, rebought, then leveled to max, Mastery XP will be gained for all levels achieved beyond the original level."