My stylist does this too, but the minute she turns her back, I increase it to a minimum of 30 minutes. I don't know it fhtey just want to hurry on to the next client or they're saving up on energy billserplexed, but I think my hair needs more than 15 minutes of DC'ing. When I DC at home though, it's for a minimum of 40 minutes to an hour.Well I get it deep conditioned at the Dominican salon, and they usually set the drier for fifteen minutes. I dont know if thats standard, or a bit shorter.......
I deep condition under a hooded dryer for 15 to 20 minutes. I have read after about 10 to 15 minutes the cuticle is as open as it gonna get and absorbs as much as it's gonna absorb.
With heat: 30 minutes
Without heat: Until....... Sometimes I leave it in my hair for hours if I'm busy......or watching an interesting movie...or two. I've even left it in overnight on several occasions to no ill effect. But I always use a cap.