Terraforming Mars' card economy creates a situation where buying fewer cards is sometimes correct. The standard hand is ten cards at session start and three cards per turn at the draft cost of three credits per card. Passing on all three cards when none serve your corporation's strategy preserves credits for other purchases.

New players often buy every card they can afford, creating expensive hands that reduce their ability to play other cards. Experienced players evaluate each card against their current strategy and pass on cards that do not advance it. The discipline of selective acquisition is the game's primary economic skill.

For teaching Terraforming Mars: explicitly explain the three-credit acquisition cost and why it matters. The concept that buying a card is an investment that should be evaluated before the buy is non-obvious to players coming from games where drawing cards is free.