Anyone playing Planescape Torment? Magic question.

I picked up the game used, but no manual. Good so far, managed to figure out most stuff. I am wondering about the spell system. You have to rest to read/learn the spells but can only use them once before resting/relearning them. Does this change, as far as how many times you can use a spell before resting, when you level up. I can't find any info on this game as far as magic use goes.

 

If you're familiar with D&D, then the system's pretty easy to understand. Otherwise;
As you level up, you can cast more spells in a day before you need to rest, and higher level spells become available.