Shampoos that help maintain hair color and selecting a shade that fades beautifully are both crucial.
However, one of the best coloring methods for long-lasting color is: highlights or a color technique that incorporates highlights.

The need for a color touch-up is usually determined by how much new hair has grown from the roots. Since highlights primarily color the ends rather than the roots, regrowth is less noticeable, allowing the color to last longer.

Many of my clients go more than six months without needing a touch-up, and some only color their hair once a year!
If you're interested, consult with your stylist to find the best option for you.