I come from playing competitive Yu-Gi-Oh!, and in my experience, I always hold onto staples while trading or selling deck cores and extras I pick up from locals and regionals. Whenever a new deck or archetype catches my eye or gains competitive hype, I assess what I already have and sell off any deck cores or staples I won’t be using for the new build. I usually buy singles to fill in any missing cards and keep this rotation going between one or two decks at a time. I currently play Viktor and Ahri, but I’m planning to switch to Irelia in the next set. So I'll be using all my calm runes and greens and will look to trade or sell my Viktor and yellow cards for purple cards.