How many cards should you have in your deck?

[Hannah Barbara]

I'm lazy I just put every card in my deck.

[Captain Murphy The Villian]

40 regular cards 9 items

[Shadom]

49, 9 items and 40 cards

[BirdDinosaur]

I believe you can have as ma ny as you want but the thing is if you have too many, your deck becomes more inconsistent. So generally you want less cards in your deck so you can reliably play cards and predict which cards are going to come out when you need them. 40 is the minimum and is probably the best for consistent decks but if you have 50 or more then you might have to get yourself some draw a card mechanics but even then it won't be very reliable. Youu'll end up with a whole bunch of cards in your hand that you probably won't use all in one game. Other games have cards that will allow you to draw specific card types like draw a card with condemn or draw a 2/2 blue card but artifact is new and probably won't have any of those kinds of draw cards until their card pool reaches any where of up to a 1000 cards. So as sachi says, 40 and 9 items is the optimal amount for consistent decks. The mathematicians will agree with that figure too. It doesn't leave much room for flexibility but you will be able to rely on your deck more and have less of those "where the ♥♥♥♥ is that card?!! moments.

[Wutproppen]

The fewer cards the better, as it's then more likely for you to get any combos going. For example: opponent runs annoying improvements, I know I have some demagicking mauls in my deck that destroy improvements. With a huge deck I'd have no idea when I'd draw them. With a small deck I could be sure to draw them any time soon.

Having more cards than necessary might be useful if either mill decks would be a think (that would win by making you run out of cards) or if there'd be cards rewarding you for having a big decks. But neither is the case.

[Esxhaton]

Deck size matters.

[Kopejka]

Originally posted by Youmu Konpaku:

I just put every card in my deck.

You must win a lot with your deck.

but as others said the minimum is 40 cards, 9 items.
I personally use like 41 cards and 12 items or something like that

[Kawira]

It's always balance thing. Smaller deck - more consistent, easier to get what you want but very limited in terms of strategy, bigger deck - more flexible but also more random. I tested few variants and for me 47 cards is optimal number but for every person it may vary.