I have some house rules in mind concerning ingredients and magic. I have not tried them out, so it is just a brain child so far. (I appologise beforehand if I do not use the correct english terms, I have only read through the swedish version so far.)
1. Ingredients are mandatory. I have always been a bit annoyed by the fact that spell casters don´t use "tools", but all other characters need stuff to do what they are best at. (The warrior needs his sword, the thief needs his lockpicks, the hunter needs his bow etc). Also, it is a "mood-thing". Spell casters in pictures, movies and books often carry around a lot of "random" stuff. (Herbs in the belt, amuletts, a "troll-drum", a ritual knife, a staff, wierd clothes etc). Why do they do that, if there is no need for it?
2. Mandatory ingredients should be relatively easy to come by. If it is a little harder to come by (Say a skull from a human, or a mirror) it can be used for as many times as you like, until it breaks. (Like a warriors sword.) If it is really easy to come by (say a handfull of small rocks or a common herb) it is an expendable resource and you might use a rerource die to determine how much of it you have. (Like an archers arrows.)
3. Not every spell caster need to use the same ingredients for the same spell. The player desides beforehand what ingredient is needed. The ingredients listed in the book is help/inspiration.
4. The player must beforehand explain how the ingredient is used.
5. Volontary ingredients raises the effect of the magic like stated in the rules. Volontary ingredients are harder to come by. (Like a rare herb picked at midnight, the burial shrowd from a person who committed suicide etc). It works the same way as the mandatory ingredients - if it is hard to come by (Like a rare herb or teeth from a troll) it is an expendable recource, and if it is really hard to come by, (like a dragons tooth or a piece of a fallen star) it can be re-used.
6. There are exceptions.
¤ "Stone-song" magic. Recuires a successful roll in singing, (Skaldekonst in swedish), not a volontary ingredient, to get the extra effect. (They never need to bother about the volontary ingredients, but there is a chans of failure. A little good - a little bad)
¤ "Symbolism". The caster needs to make/paint the rune beforehand. It can be used as many times as you like, as long as you have it, but there is no way to get the extra effect. (So no expendable recources, but no extra effect. A little bad - a little good, but more bad than good. I must admit I am not very happy with this idea, and still thinking about how to make it better.)
I am aware that not every person will like theese ideas, since it makes playing a spell caster a bit more difficult. But I feel that it will bring a nice mood to the game, and I want the spell casters to stand out as original people with interests that is hard for other people to understand. ("No wait, we have to stay here another day. Tomorrow there is a full moon, and this tree is the perfect size". "Perfect size for what?" "Never you mind. Now, where did I put my sickle?")