About half a cup to a cup depending - A LOT, basically. I have a lot of hair, it's long, it's coarse and porous and it's transitioning from chemicals so dryness is a concern. I do shampoo - every one to two weeks with a mild sulfate - and then I don't wet my hair in between, so the leave-in has to last me that long. HTH!
Get used to me. Black, confident, cocky; my name, not yours; my religion, not yours; my goals, my own; get used to me. -Muhammad Ali