I'm new to magic so I'm looking for some deck building parameters. I wonder at what point are cards generally just to expensive to cast. I found this article interesting, though it's from 2009 so maybe things have changed. Of course it depends on the deck you're running, some quick decks might not have anything over 3 converted cost, some combo decks may manage to play very expensive cards. In my very limited experience as a casual player, 5 mana cost seems viable, 6 risky, 7 barely playable and anything over that not viable. What might be a good rule of thumb for a starting player?