Board Thread:Game Discussion/@comment-17706575-20130924161525/@comment-24003266-20131022210818

Yeah, the EP required per level increases as your armor level increases; although, 3*, 4* and 5* sets level at same rate up to 70. It requires a total of 5,080 EP to max a level 70 (Ultra rare or Legendary) set and 9,030 EP to max a level 99 (Epic) set. FYI, it requires 1,664 EP to reach level 35 and release + version of Legendary armors, including Epic Boss sets.

RoP is correct in stating that you want to get through the upper levels as quickly as possible b/c it becomes very expensive and time consuming once above level 50 or so. Use the guaranteed basic combos to receive 50EP non-craftable sets for enhancement once your armor reaches ~level 50, if not sooner.