Most games released today are expected to have at least a 5-year lifecycle with patches and expansions. As the original design team moves on to new jobs, they must be careful about what they design and try to lay down a set of best practices to prevent new designers from creating new features that accidentally break the game. Hearthstone's Grand Tournament expansion provides good examples to look at. The Tuskarr Totemic, which summons one other card labeled "totem" into the game when played, is currently balanced since only one-third of totems are strong cards. To prevent this card from getting out of control, Hearthstone designers will need to maintain that ratio or the odds of the Tuskarr Totemic completely changing the board in favor of the player who uses it get out of control. On the other hand, the Druid's Living Roots card is currently balanced, but has much more potential to unbalance the game because it can be used to summon multiple small creatures. This opens the door to combinations: any time another card (like Savage Roar) rewards having more creatures on the board, Living Roots can become unbalanced. Finally, there is the new Druid card Astral Communion, whose properties boil down to "win the game immediately" or "lose the game immediately." This card accelerates late game in such a way that it basically has to be unplayable (like it currently is) or it completely breaks the game, making it a risky card to release and an interesting choice from Hearthstone's designers.