Yes, you can leave chebe or shebe powder in your hair for up to 7 days (curly/coily hair) or up to 3 days (straight/wavy hair). You are not actually leaving the powder in your hair for this duration of time - you are leaving a paste made with the powder plus oil or water. The paste will harden over the span of a few days, making it a little challenging to remove. Shampooing twice should remove the residue.