Stacking spells = discount on mana

I was testing my first caster on Thessir, just a ranger but I have noticed there is no point in preparing the same spell more than one time, so here is my suggestion:

Since you get less variety of spells, stacking the spell various times should give the char a discount when casting the spell based on how many times the character have it prepared on their spellbook. Dunno if it's possible, but the idea of sacrificing variety in exchange of a discount on the cost should compensate that, and give players a good reason to don't have the entire spellbook prepared

Susurros wrote:Dunno if it's possible

It basically isn't. Sorry. Just enjoy having unlimited casts of your spells.