To repost from another thread:
The way that I teach ALL forms of magick taps you into a limitless well of power, from which you can draw endlessly in order to project your vision into reality.
That being said, the vehicle of transmission does need to adjust itself to such high levels of energy passing through it. So, when you charge one sigil, you might feel a certain exhaustion. You’ll find that with repetition, you’ll be able to do more and more before hitting that ceiling.
However, it’s not a matter of drawing from your own lifeforce (with the idea that your lifeforce is limited), that causes the exhaustion, but just the fact that your body is funneling an impressive amount of raw power!