Can I mix older Magic the Gathering cards with cards from Magic 2015? If I have mainly Magic 2015 cards can I play my friends who mainly have older decks?
It depends on what format you want to play.
You can use whatever cards you want, as long as your friends are alright with it. This is informally known as "kitchen table magic", at least in my area. Some casual formats are are so popular that they have their own rules, such as Commander. See the link at the bottom for more information.
Prior to 2016, you could only use cards from the latest two expansion blocks and any core set(s) directly succeeding them. Starting in the Spring of 2016, you can only use cards from the latest three expansion blocks. For those unaware, a "block" is a set of expansions that are released sequentially and revolve around a single story or plane. More details on this format here.
You may use cards from any set since 8th Ed. Some cards are banned.
You may use cards from any set. Some cards are banned.
You may use cards from any set. Some cards are banned. Others are restricted to one copy per deck.
All Constructed Formats
The following rules apply Standard, Modern, Legacy, and Vintage.
- Deck must contain at least sixty cards
- With the exception of basic lands, decks may not exceed four of any card
- Cards with a silver or gold border only are illegal
- Decks containing a mixture of Alpha and non-Alpha cards must be played with opaque sleeves
- A card from an older set is legal if a card with the same name was printed in an otherwise legal set
You can learn more about these formats, as well as some that I did not cover (such as Commander), by visiting Wizards of the Coast's website.