I have long hair and I also color and highlight it,my dilema is?

within 4 wks of having it done my roots begin to show I always use very good hair products out of the salon but it doesnt seem to matter what I use it still happens,I have gone within the 4 wks after originally having it done but it gets costly.any suggestions

I have long hair and I also color and highlight it,my dilema is?

highlight your hair that will blend with your natural color.

this way when your hair grows out you will not see the definate line.