Mana/energy costs
Abilities and cards cost a spendable resource — mana, energy — that regenerates or accrues over time, forcing players to budget their most powerful actions. Cost systems are the fundamental throttle on power: they prevent spamming the best option, force sequencing decisions (spend now or save for a bigger play), and let designers price abilities relative to their impact. Slay the Spire's per-turn energy and Hearthstone's escalating mana crystals both make 'what can I afford this turn' the core decision. Designers use resource costs to pace power, to create meaningful tradeoffs between options, and to enable ramp/efficiency strategies. Key decisions: regeneration model (per-turn refill, escalating pool, or slow regen), whether the resource is bankable, cost-reduction mechanics, and the granularity of the economy (few large costs versus many small ones). Pitfall: costs that don't scale with power let a single overtuned cheap ability dominate — the whole system depends on cost accurately reflecting impact, which is perpetual balance work.
- Dev effort: Small
- Timing: Real-time or turn-based
- Common in: card-game, rpg