It primarily depends on each person's habits, the texture of your curls, and your scalp, so there is no universal rule. As a general guideline, a full wash with shampoo, followed by conditioner or mask, about once or twice a week is recommended. This is intentionally less frequent than for straight hair because curls have a spiral structure that retains natural sebum less effectively: washing them too often could dry them out more, while a reasonable interval helps preserve their hydration and natural definition.
Between full washes, it is not necessary to redo the entire routine from the start to restore beautiful curls. This is where leave-in treatments really come into play: a few dollops of curl definition gel re-moistened with water, or a small amount of oil serum on the ends, instantly reactivate definition and revive curls that are tired or flattened from the night, without needing to shampoo. This trick is especially useful at the end of the week when curls start to lose hold but the hair doesn’t yet need a full wash.
If you’re unsure about the best washing frequency for your situation, the Curl Diagnostic takes into account your hair’s porosity: very porous hair absorbs and loses moisture more quickly, which may justify a different washing or touch-up schedule than less porous hair that retains moisture longer.