Well I usually do a deck clear every so often when I notice my decks have stop being functional I throw it out. As for how me I get an idea of what I want to see or happened then I execute that idea I have sacrificed legendary to get the amount of points I need to buy a card I want and is not that big of lost as you may think. The way I have looked at it Legendary are great as long as you can support them I use to ha e to barrel zombies and I notice if I place them at the wrong time I would have screwed myself over or my mechanical shark put him down and watch him die. Cornucopia is one of the few legendary I don't sell that and the trickster sometimes you have to understand that if you get legendary and make a deck the legendary gets in the way of your synergy and if you make a deck that supports that legendary you screw yourself over cause decks like those are not adaptive as you think....which is why yo avoid future losses I replace my decks and cards in my deck with adaptable cards.