Well, when I call myself deep conditioning my hair, I've either 1) Left the conditioner on for about 1 hr. (no heat) 2) Left the conditioner on for 30 min. (heat by hooded dryer), or 3) Left the conditioner on overnight. Really, just allowing my hair and the conditioner to really get to know one another. I do this every time I wash, which is every 5 days.