Why the minimum matters in deckbuilding
In ordinary constructed Magic, the 60-card minimum is a floor, not a target enforced by the rules. Players may register larger decks, but competitive lists usually stay close to the minimum because drawing a card is effectively drawing one at random from the library—the deck’s draw pile. With fewer cards competing for each draw, a particular key card, or a useful combination of cards, is easier to find.
That consistency matters because a deck is more than a pile of individually strong spells. Its cards are meant to work together: a low-cost creature may buy time for a powerful spell, while a card that searches the library may help assemble a specific plan. Adding cards that do not advance that plan makes the deck less focused; adding more copies of the same role can make its opening hands more dependable, subject to format rules on how many copies are allowed.
When extra cards can be worth it
A larger deck is not automatically weaker. It can make sense when a strategy benefits from having more options, when a format requires a different deck size, or when a player wants protection against effects that remove cards from the library. But each addition is a tradeoff: it gives the player another possible draw while also lowering the chance of drawing any particular card already in the deck.
So the 60-card minimum creates room for choice, while the incentive to stop there creates a sharper design constraint. Every slot has to justify its place—not just by being useful, but by being more useful than the card it could replace.
