Type of dye: Temporary dyes last 1-2 washings, semi-permanent dyes last 2-6 weeks, and permanent dyes can last several months to a year.
Color formulation: Lightening hair dyes tend to fade faster than darker shades.
Porosity of hair: Highly porous hair will absorb dye faster but also fade faster.
Hair care: How often you wash your hair, the products you use, and exposure to sunlight can also impact the longevity of hair color.
On average, permanent hair dye lasts about 4-6 weeks on the scalp and 2-3 months on the ends. It is important to follow the aftercare instructions provided by the hair dye brand to maximize the longevity of the color.