I have curiously strong opinions about some things, and Magic deck size is one of them. In Magic, decks have a minimum size (60 for constructed, 40 for limited) but no maximum size. A lot of people will feel that they more card love than a 60-card deck can hold or can’t bring themselves to remove any of the current cards to make room for new ones. That is a mistake. Magic’s randomness is the bane of all players. One of the best way to finesse your game is to tip the odds in your favor, and an easy way to do this is always play with the minimum deck size allowed.

Let’s say you add that 61st card. The hidden cost is that by drawing the new card, you don’t draw one of the other cards. If you are able to objectively grade all of your cards, then it’s easy — removing the “weakest” card increases your drawing the other, better cards. So by adding that 61st card, you are effectively saying there is then no weakest card (i.e. that all your cards have equal strength). I’ll bet you can find a card worse than the others in your deck.

Of course, you can’t always objectively grade your cards; your deck will have groups of cards for different purposes. Even so, your deck will have certain components that you will need from time to time. For example, Wear Away or Kokusho. By increasing the size of your deck, you are decreasing your chance of drawing those cards when you desperately need them.

If you have so many different strategies present in one deck that you need more than 60 cards to hold them all, I would argue that you need to focus more. Multiple deck directions breed poor consistency.

The argument that a larger deck protects against running out of cards seems inconsequential in comparison with the far more tangible benefits above. You never run out of cards. Unless the metagame specifically suggests it, you don’t need to worry about Millstone decks. Besides, there are better ways of dealing with Millstone than a 200-card deck.

Now, there are technically situations in which it would be good to have more cards. If you are really fine-tuning your percentages and you have access to many different, functionally-equivalent cards, then it might make sense. You could increase the number of all cards but a few to slightly decrease the chances of drawing them or other similar adjustments. But in practice, cards aren’t so equivalent and 60 cards is plenty of room to finely set percentages.

I would say it is far better to set percentages by decreasing the size of your deck. Using cards like Conjurer’s Bauble or Reach Through Mists lets you play with an effectively smaller deck, in turn improving the consistency of the meat of your deck.