I am not sure which cards to disenchant.
Should I disenchant all the cards which I don’t use or should I try to collect at least each copy of a card.

Hello, I am new player I have been playing for almost 2 months now and want to buy an expansion. I am confused about investing in witchwood but the deal of 70 packs sounds good.
What should I do. Buy it or not ?
Will appreciate suggestions.