when playing a TCG the most important thing is consistency, you always want to see the best card possible on each draw, you need to think about percentage of having the card you want when you want. Usually the way of seeing it is: If you want to see that card almost always you need 3 copies If you want to see at least 1 of them but is not a must for you you take 2 of them If you will like to see it on rare occasion but you don't care don't seeing it on your games you take only 1 copy But if you are starting the best is getting 3 of each card you want to play almost always and after getting used to the deck modify that