How often does henna hair coloring need to be reapplied to keep the color fresh?

(this is with using body art quailty red henna)How often does henna hair coloring need to be reapplied to keep the color fresh?
every 2-3 monthsHow often does henna hair coloring need to be reapplied to keep the color fresh?
As much as you like, but at least every six months for strong shine and color. More often if you don't like roots. But for me henna blends in better with my natural roots, so I can ignore them longer.