What's the difference between a rinse-out conditioner, a deep conditioner, and a leave-in?

A rinse-out conditioner is used in the shower after shampoo and washed out within a minute or two for everyday detangling and softness. A deep conditioner or mask sits on the hair longer (often 5–20 minutes) to deliver more intensive moisture or repair, typically once or twice a week. A leave-in is applied to damp hair and not rinsed, adding ongoing slip, frizz control, and often heat protection.