The main difference between leave-in conditioners, conditioning masks, and regular rinse-out conditioners is their purpose and intensity.
Rinse-out conditioners are designed to be used after you shampoo your hair. They are formulated to replenish moisture and nutrients lost during the washing process, and to help detangle and smooth your hair. Rinse-out conditioners are usually lightweight and don't leave a heavy residue in your hair.
Conditioning masks are designed to provide an extra boost of deep conditioning and nourishment. They are typically thicker and more intense than regular conditioners, and are used once or twice per week as a deep conditioning treatment. Conditioning masks are formulated to deeply moisturize and nourish your hair, leaving it soft, shiny, and healthy. They are great to use if you have dry or damaged hair, or if you color or chemically treat your hair.
Leave-in conditioners are formulated to be applied to damp hair after you have finished washing and conditioning. They are typically lighter than conditioning masks, and are designed to help detangle and manage your hair. Leave-in conditioners penetrate deeper into the hair shaft and coat your hair to provide extra moisture and nourishment. They are great to use if you have dry or damaged hair, as they can help to protect your hair from further damage.
Leave-in conditioners are applied to wet hair after shampooing and conditioning, and are meant to be left in your hair without rinsing out. They help your hair to maintain moisture, prevent tangles, and protect your hair from damage caused by heat styling tools or the sun. Leave-in conditioners can be used daily or whenever your hair needs extra hydration.