So I haven't been playing hearthstone for that long, but I've played a lot of other card games before. One thing I'm confused about is the prevalence of high-level decks that run 1 copy of a (non-legendary) card. In many other card games, you generally want to run the maximum number of copies of each card, because otherwise you're introducing too much uncertainty into your deck.
Can someone explain to me the prevalence of using 1 card instead of 2, and what situations you would do this in? I like to build all of my own decks, and this seems to be an important concept.
Best Answer
I feel like your question is starting from an invalid premise. Hearthstone is no different from other card games when it comes to how many copies of a card you want in a deck (barring the obvious differences of how many cards you can have and how many copies are allowed).
In Magic: The Gathering, there are common strategies for putting anywhere from 1 to 4 copies of a card in your deck. I even looked at some recent Magic: The Gathering top decks and saw Akito Shinoda's deck which won the Grand Prix Shizuoka 2015 which ran a single copy of 17 different non-land cards. This is a top deck in a card game that allows four copies of a card.
In most card games, there are strategic reasons to use less than the maximum number of copies of each card.
So, onto Hearthstone! One thing to realize about many top Hearthstone decks is that they tend to run a variety of cards that draw cards. This means often when a player gets to the maximum mana (on their 10th turn), they have already drawn two thirds or more of their deck. This means that running multiple copies for reasons of consistency only matters for your first few turns. Here are a variety of reasons that you would only run 1 of a card in Hearthstone. You may note that these reasons are similar to the article on Magic: The Gathering.
In addition to all of these examples, sometimes it is just a matter of not having space for two cards. For example, if I used an odd number of legendary cards in my deck, I'd have to choose to include only one copy of some non-legendary card.