Lots of free but the gears you work hard for can easily go to trash upon tier upgrade because stats are randomly given and can't be changed. It's possible to get trash stats for endgame like Gold Increase or Exp Increase on your Mythical Plus gears so you have got no other choice but to disassemble and start all over again. All efforts wasted, resources not fully refunded while success rate plummets. That's just pretty punishing and toxic, even if you use Diamonds (Premium Currency).