Untested house rule for the White Sandbox:
If you can cast spells, you can prepare extra spells when you have assistance throughout the process of memorization.
One assistant of your own level can help you memorize an extra spell of the highest level you can cast. It is common for adventuring parties to help each other in this way.
You need an additional assistant for each level of spell below that. These old magics aren’t as interesting to you, you need more people involved to get excited about these lesser levels of mastery. In the picture to right we see a third-level magic-user who has recruited a dancing twin and an old carpet-scriber to inspire her to focus on charm person when she’d really rather fool around with knock. When she reaches fifth level, she will require one assistant to memorize an extra fireball, two to memorize an extra knock, and three to memorize an extra charm person.
Assistants must be compensated beforehand. At least one of your assistants must be a spellcaster of a level equal to the level of the spell you are trying to memorize. Zero level assistants will help for nothing beyond the services listed below; higher level assistants may be hirelings paid as per the Adventurer Conqueror King System rules, but will also require these services.
Lawful types traditionally cast a spell that serves the assistant’s goals. This must be done within a day and a night before the memorization takes place.
Neutral types traditionally give the assistant a page from a book which they have written or annotated. If the assistant is not happy with the page offered, they have the right to take a page at random from any of the spellcaster’s books; it is thus standard to negotiate carefully beforehand.
Chaotic types traditionally provide the assistant with a helpless living creature of hit dice equal to the assistant’s, and allow the assistant to do with this creature as they wish.
Other forms of recompense are possible, but these are known to satisfy the requirements of the ways of spellcasting.
The goal of these house rules is to further encourage characters to travel with an entourage, like how Gene Wolfe’s wizard-knight Abel accumulates squires and servants, and provide a way for the entourage to be doing interesting things in the preparing-to-go-into-a-dungeon phase of play. Note that if, as in ACKS, memorizing a spell means having it available to cast spontaneously, allowing these extra spells increases the caster’s flexibility but not their overall power level.
Next up: assistance for fighting men to increase their hit dice on similar principles.