Do sideboard sleeves have to be the same as main deck sleeves, or can you use different sleeves or go sleeveless?

Ruling: There is no specific rule requiring sideboard sleeves to match main deck sleeves. You can use different sleeves for your sideboard or even go sleeveless, though this is strategically disadvantageous.

Nuances:

• The only hard rule about matching sleeves is that all sleeves within a deck must be identical and cards must be placed in sleeves in the same manner
• Using different sleeves for sideboard cards reveals to opponents how many cards you swap between games
• Re-sleeving takes up unnecessary time during matches
• It is suggested (but not required) that players use different sleeves for different decks like Main and Rune decks