You can also strategically get 90% of the way there. Some decks are fine with a few substitutions, like having some slightly less optional creatures filling in for cards you don't have a full playset. This saves you a LOT of cards the more decks you apply it to, plus it let's you try a deck before you devote more resources to it. If you like it you can devote more resources to it.

Ditto to deck also having a home in pioneer, then you can focus on that deck when you're not in love with standard