A wizard can cast a spell without spending a spell slot (or spell points or whatever) . This ritual requires:
- 10 minutes per spell level squared in the casting. During this time, the caster must devote all their energies into this: they cannot be riding, or be interrupted, or eat (they may drink, if the drink is handed to them).
- Incense and so forth equaling 10gp per spell level (in addition to any other material components required by the spell). Each assistant reduces the cost by 1gp.
|Spell Level||Casting Time|
|4th||2 hours 40 minutes|
|5th||4 hours 10 minutes|
|7th||8 hours 10 minutes|
|8th||10 hours 40 minutes|
|7th||13 hours 30 minutes|
If the spell wasn’t prepared, the caster must succeed at an INT check (DC 10 + spell level, or with a penalty = spell level, whichever is more appropriate). Otherwise the spell fails and the time and incense are wasted.
[This has the effect of making spells like detect magic much easier to use – there’s no need to skip it because you want an extra magic missile. 5e came close, but it only allowed a few spells to be rituals (which I feels stifles creativity). Also, I quite like the idea of high-level spells being cast as all-day rituals.]
Another option: allow PCs to study/pray to swap out memorised spells during the day: this takes 10 minutes per spell level, and a successful INT/WIS check (as above).