Prepared vs Spontaneous Spellcasting
Prepared casters choose spells each morning for specific slots. Spontaneous casters know fewer spells but can cast any known spell in available slots. Signature spells heighten freely.
PF2e has two major spellcasting models, each with distinct strengths.
Prepared Casters (Wizard, Cleric, Druid): Each morning during daily preparations, you choose which spells to place in your spell slots. Each slot holds one specific spell at one specific rank. If you want to cast Fireball twice, you must prepare it in two separate slots. Prepared casters have access to their entire spell list (or spellbook for Wizards) but must predict what they'll need.
Spontaneous Casters (Sorcerer, Bard): You know a fixed repertoire of spells. You can cast any spell in your repertoire by spending an available slot of the appropriate rank. You don't need to decide in advance which spells go in which slots. Spontaneous casters have fewer spells known but greater flexibility in how they spend slots.
Signature Spells: Spontaneous casters designate one spell per rank as a Signature Spell. Signature spells can be heightened freely — cast in any slot of equal or higher rank. Non-signature spells can only be cast at the rank you learned them.
Spell Slots: Both types get a limited number of spell slots per rank (typically 2-3 per rank, increasing with level). Cantrips are unlimited-use spells that auto-heighten to half your level.
Key Trade-offs: Prepared casters have wider spell access but must guess right. Spontaneous casters have narrower options but never waste a slot on a spell they don't need right now.