Casters with low main stat

[Jacob Saltband]

What happens to higher level slots if a caster with a low governing stat stay in the class and gain spell slots for spell levels higher then their stat allows?

[Michael Sayre]

You can use the higher level slots to memorize lower level spells.

"Spell Slots: The various character class tables show how many spells of each level a character can cast per day. These openings for daily spells are called spell slots. A spellcaster always has the option to fill a higher-level spell slot with a lower-level spell. A spellcaster who lacks a high enough ability score to cast spells that would otherwise be his due still gets the slots but must fill them with spells of lower levels."

[-Anvil-]

Jacob Saltband wrote:

What happens to higher level slots if a caster with a low governing stat stay in the class and gain spell slots for spell levels higher then their stat allows?

Ssalarn beat me to it, but yeah basically that's what you'd have to do.

A better option is to save up for a magic item that enhances your primary casting ability or else you'll find yourself becoming quickly obsolete as you get higher in levels. Monsters will easily overcome your spell saves due to a low modifier and the lower level spells just won't hold up at higher levels no matter what type of caster you are.

[Ciaran Barnes]

You can use higher level slota to cast those low level spells with meta magic applied as well.