I only stay for 20 minutes. I used to do it for 15 but I added 5 extra minutes, because I didn't think 15 was enough. If I'm doing a protein treatment I'll steam for 20 minutes with my protein conditioner and then do another 20 minutes with my moisturizing conditioner. I get antsy after steaming too long. I'm constantly looking at the time to see if my time is up.