The core rulebook for Heroes & Other Worlds discusses how player-character wizards can acquire new spells (page 51); these houserules presented here seek to quantify this and explain how I look at this learning experience 'in-game'.
For my campaign, there are two ways for a wizard to acquire new spells: research from a written source (be it a dusty, old tome or a scroll); and being taught by another wizard.
FROM A WRITTEN SOURCE: To learn a spell from a book or scroll requires serious study of the text for a number of days equal to half the required IQ of the new spell (e.g. a young wizard learning a new IQ 8 spell would spend four days reading, taking notes, testing, experimenting etc).
This study occupies eight to ten hours of every day, so the character isn't available to pursue other endeavors while doing this.
At the end of this time, a 4/IQ check must be made by the reader and a two dice check must be made against (20 - the Required IQ of the spell). Failure on either check means the reader has to begin again, spending the same number of days before making another pair of checks.
- NB. As these are 'magic checks', fumbles/mishaps are possible on high rolls, with any misfortune indicated being suffered by the reader.
FROM A TUTOR: Not all spells are readily available in written form, sometimes a wizard has to sweet talk one of his peers into teaching him a new spell.
The teaching process takes a number of days equal to half the required IQ of the spell being taught, and during this time the student is occupied about eight to 12 hours a day, and the teacher about five or six hours a day.
At the end of this time, the student must make a 3/IQ check and the tutor must make a 3/(IQ+Level Of Spell he is teaching) check.
Failure on either test means the lessons continue for a similar period of days before another couple of checks are made.
- NB. As these are 'magic checks', fumbles/mishaps are possible on high rolls, with any misfortune indicated being suffered by the person making the check.