Differentiate spellcasting greatly for the different types of spellcasters:

• Intelligence casters have a spellbook limited by their level, where higher level spells take up more space.
  • Specifically, they can store up to (10 + XL) levels of spells.
  • Higher skill in a spell’s school provides a discount: 1 level for Basic, 2 for Skilled, and 3 for Expert.
  • So for instance, a level 5 character has 15 spell levels available. If they know force bolt and are Unskilled in attack spells, that takes up 1 level. If they know cancellation and are Skilled in matter spells, that takes up 5 levels (7 - 2 because they are Skilled).
  • When they learn a new spell that cannot fit into their existing spell list, they are prompted to forget known spells until they have enough space, or decline to learn the new spell (which still uses up a read charge on the book).
• Wisdom casters always have all the spells they have learned available so long as they haven’t forgotten them, but are strictly limited in whether they can cast a spell of a given level by their skill in its spell school.
  • If Restricted in a spell school they can only cast spells of up to level 1. If Unskilled, up to 2. Basic, 3; Skilled, 5; and Expert, 7.
• Charisma casters (which only exist in a couple variants) always have all spells available to cast, but can never cast spells twice in a row; there is always a cooldown of (5 - skill) * 2 * spell level. (Skill ranges from 0 at Restricted to 4 at Expert.)