Hello, at the moment I am following this policy when I win a card during spins: I sell it right away if I have six unupgraded copies and six upgraded copies of that card. The ratio behind this reasoning is that I might want to use six copies of that card in a deck and for some reason I might want to use it unupgraded. This is mainly due to some cards changing they behaviour a lot in their upgraded version, for instance Toadfish loses its creature control abilities in the upgraded version, unupgraded Pandemonium can be useful in a Voodoo Doll-based deck and so on. However, most cards do not make much sense to be kept unupgraded (for instance SoRe, SoSe, SoSa, SoFo and many others). Now my question is: apart from cards that change their behaviour when upgraded, is there any good reason for not selling unupgraded cards (in particular rares) when one already has 6 upgraded copies of them?